I have just returned from Tokyo, and was lucky enough to acquire a beautiful example of a first generation Seiko Automatic. As it happens it is precisely the one illustrated in the 1959 catalogue/brochure that you kindly posted on the forum.
Would you be so kind as to check to see whether there are any further details in that brochure? It is the steel one in the center of the yellow page, with the ref. "A - 8", and arabic "12" on the dial.
If there are any further details, I would greatly appreciate it if you could post them!