If we're talking American builders I think it might be hard to pin point the year down (unless buying from the original owner).

Some other folks that were making frames then - Bilenky (under Sterling label) and Franklin Frames (one member here has a beauty from them) come to mind. I'm not sure if Redcay was still building by that point or not, but I really like his stuff a lot.

Serotta with DA 7400 - classic in my mind, and Serotta are often available at reasonable numbers.