Originally posted by Ira My 1.9 # is 252xxxx and that's not listed on that site.
But only goes to 16.
I'm not sure what you mean by "its not listed on that site." If yours goes to f1.9 to 16, its version 2 of the Super Tak. Based on the serial number, I'd guess that yours was made in late 1967. The f1.9 to 22 version was made from about 1962-64 and version 2 from about 1965-71. and the S-M-C f1.9 was made in 1971 & 1972. On that particular page he doesn't mention that there were 2 versions of the S.T. On one of his main pages he also mentions he stops his collection concentrates on Auto Tak and earlier.
Note: The serial numbers are based on the defunct but uncompleted m-forty two project. I have a copy of the lenses and serial numbers and are intended as a guide. They were based on data submitted manly by private collectors.
Edit: Go here for a listing. AOHC isn't perfect for example actual m42 production probably stopped across the board in 1976. However, stocks kept them in the catalog through 1979.
http://www.aohc.it/tak04e.htm