Firstly, sorry my posting skills are rubbish - so attachments may be out of synch.
Well I asked the question recently about the STP mark on '60s Seiko watches.
I found that this was an oft asked question across many watch forums, and I still couldn't find any satisfactory answer.
I thought I'd have a look at some old Seiko catalogues to see if I could find some examples of the STP watches. I found what I wanted, in the forum here ( in 64_6)
http://www.thewatchsite.com/13-ads-...dealer-catalogues-tokyo-olympics-edition.html
Harry from Denmark had kindly uploaded some '64 Olympics Seiko dealer catalogues, and I found this page. (see attached pdf )
But I couldn't find the usual glossary to explain the abbreviated case designations !

(.
So I looked very closely at the STP sign and it's next nearest one, and saw the Japanese characters following them were very slightly different (under magnification)
So I duly downloaded an OCR program to copy the text and searched for the Japanese symbols online....... and after a hunt found a Japanese watch blog which had mention of the symbols in question.
This is a copy of the Japanese and English translation
SEIKOの腕時計の側質には下の32種類がある。
ステンレスっていっても、SSとSTP・HSSの3種類が有る。
ややこしいこと極まりないのが、金張。
SGP・ASGP・GCとあって、GCは厚さに結構幅がある。
14Kと18Kもあるし・・・
現物見れば金無垢だと、重さが違うからすぐわかるけど、写真だとこれだってぱっと見わかんない。
ヤフオクで最近気になるのが、18K無垢って出品してるけど、GCだったり、ASGPなのにGCって記載してあること。
はっきり言って「記載内容に誤りがあるぞ!」ってこと。
GSばっかり見てたときは知ってるからいいけど、KSのGCなんて書いてあると、「おおっ!」っとなって入札しそうになっちゃう。 (KSにもGCあるけど、超稀少らしい。)
Lord Marvel・Cronosあたりの18K無垢モデルなんて、あったかどうかさえも良く知らなかったんで、「おおお!」って感じで感動するばかり。 (でも裏蓋に製品名がないととっても不安。)
なんにしても、古い国産時計は何が出てくるか分かんない。
大体、3180GSのSSモデルだって、賛否両論だし、多分SEIKOにだって記録はないと思う。
少なくとも、セイコーサービスはROREXみたいに、贋物は修理しないなんて事はないんで、「セイコーサービスの修理明細付だからホンモノ」って記述は信用しないことにしてる。
何書いてるのかわからんかったからこの辺にしよう。
1.SS(ステンレススチール側:Stainless Steel)
2.STP(ステンレスメッキ側:Stainless Steel Plating)
3.HSS(ハードステンレススチール側(硬質側):Hard Stainless Steel)
4.CRP(クロームメッキ側:Chrome Plating)
5.ACPR(オールクロームメッキ側:All Chrome Plating)
6.PDP(パラジュウムメッキ側:Palladium Plating)
7.APDP(オールパラジュウムメッキ側:All Palladium Plating)
8.WGP(ホワイトゴールドメッキ側:White Gold Plating)
9.AWGP(オールホワイトゴールドメッキ側:All White Gold Plating)
10.PMP(プラチナメッキ側:Platinum Plating)
11.WGF(ホワイトゴールド張側:White Gold Filled)
12.AWGF(オールホワイトゴールド張側:All White Gold Filled)
13.ALM(硬質軽合金側)
14.NSP(硬質合金処理側)
15.NSA(超硬質合金側)
16.AAPC(オールパラジュウム合金側:All Alloys Palladium)
17.SILP(シルバーメッキ側:Silver Plating)
18.SILVER(シルバー側:Silver)
19.14KWG(14金ホワイトゴールド側:14K White Gold)
20.18KWG(18金ホワイトゴールド側:18K White Gold)
21.PM(プラチナ側:Platinum)
22.SGP(金メッキ側:Gold Plating)
23.ASGP(オール金メッキ側:All Gold Plating)
24.NSAG(超硬質合金側:)
25.GC(ゴールドキャップ側:Gold Cap)
26.AGF(オール金張側:All Gold Filled)
27.18K(18金側:18K)
28.PC(プラスチックケース:Plastic)
29.NSB(硬質合金処理側(ブラック))
30.TWGP(ホワイトゴールドメッキベゼル付ステンレススチール側)
31.TSGP(金メッキベゼル付ステンレススチール側)
32.WGPG(金メッキベゼル付ホワイトゴールドメッキ側)
There are 32 kinds of lower quality on the side of the watch of SEIKO.
Even though I stainless steel, there are three types of STP · HSS and SS.
's Extreme in Confusingly, KimuCho.
I met with the SGP · ASGP · GC, there is a range considerably in thickness GC.
To there is also a 18K and 14K · · ·
It can be seen immediately that's pure gold and if you look at the spot, weight because different, but I do not know, at first glance even this to be a photo.
It is to be interested in the Yahoo auction recently, and have sent me 18K innocent, but that you have described or was GC, GC Yet I ASGP.
You mean "!'ll There is an error in the description," to be honest.
The good to know from when I was watching just GS, but the ratio is GC of KS Nantes wrote, it becomes almost tender Te Ttona~tsu! "Covered". (A GC to KS, but that seems to be very rare.)
I did not know well Nantes 18K solid model of Lord Marvel · Cronos per, even whether there was Nde, and just be impressed with feeling! "Crust". (Anxiety. Even if I take it when there is no product name on the back cover but)
Even so, the old domestic watch I do not know what will come out.
I think generally, SS model of 3180GS even,'s pros and cons, and that there is no record even in SEIKO maybe.
At least, Seiko service to ROREX like, not that imitation is! Not repair Nde, you have that you do not trust me to describe "real because repair specification with Seiko service".
Let around here and because I bought I do not know what you're writing.
1.SS (stainless steel side: Stainless Steel)
2.STP (plated stainless side: Stainless Steel Plating)
3.HSS (hard stainless steel side (hard side): Hard Stainless Steel)
4.CRP (chrome-plated side: Chrome Plating)
5.ACPR (all chrome-plated side: All Chrome Plating)
6.PDP (para Jewellery rhodium plated side: Palladium Plating)
7.APDP (all p Jewellery rhodium plated side: All Palladium Plating)
8.WGP (white gold plated side: White Gold Plating)
9.AWGP (All white gold plated side: All White Gold Plating)
10.PMP (platinum plating side: Platinum Plating)
11.WGF (White Gold Zhang side: White Gold Filled)
12.AWGF (All white gold Zhang side: All White Gold Filled)
13.ALM (hard light alloy side)
14.NSP (hard alloy processing side)
15.NSA (super-hard alloy side)
16.AAPC (all p-indium-alloy side: All Alloys Palladium)
17.SILP (Silver-plated side: Silver Plating)
18.SILVER (Silver side: Silver)
19.14KWG (14 white gold side: 14K White Gold)
20.18KWG (18 white gold side: 18K White Gold)
21.PM (side Platinum: Platinum)
22.SGP (gold-plated side: Gold Plating)
23.ASGP (all gold-plated side: All Gold Plating)
24.NSAG (super-hard alloy side
25.GC (Gold cap side: Gold Cap)
26.AGF (all gold Zhang side: All Gold Filled)
27.18K (18 gold side: 18K)
28.PC (plastic case: Plastic)
29.NSB (hard alloy processing side (Black))
30.TWGP (white gold-plated bezel with stainless steel side)
31.TSGP (gold-plated bezel with stainless steel side)
32.WGPG (gold-plated bezel with white gold plated side)
So, as far as I can tell -STP = Stainless steel Plate.
Information from
http://blogs.yahoo.co.jp/eheh1313/2105330.html