To answer at least one question, the bracelet on the 8021 resembles a 7 row NSA though NSA bracelets do not taper. Bracelet on the 6012 is not original to any model of 6139 i know, and I think that watch is a bit of a mishmash of parts, the dial comes from a different model as far as i know.
The 6002 on the other hand appears OK, and maybe between the other 2 movements you have enough parts to make one good one
The 6002 crown is not original (it should not be visible from the front of the case) .. Does the quick date change work? Do not force the inner ring, you will get the teeth broken. If it is stiff take out the movement and check the crystal is fitted properly.
Wear in good health, 6138/9s are my favourite Seikos
The 6002 on the other hand appears OK, and maybe between the other 2 movements you have enough parts to make one good one
The 6002 crown is not original (it should not be visible from the front of the case) .. Does the quick date change work? Do not force the inner ring, you will get the teeth broken. If it is stiff take out the movement and check the crystal is fitted properly.
Wear in good health, 6138/9s are my favourite Seikos
