That's going to be a hard question for anybody to answer beyond some generalizations.
Best somebody may come up with for a specific model would be from memory if they owned them in their day, and only an approximation of build date. The R. Lancon thing means nothing to me, but might be a key feature to somebody. I doubt factory records still exist because Redfield has changed hands so many times, so even calling Leupold may not turn up much (still the current Redfield owner as far as I know).
US patents run either 14 or 20 years depending on whether a design or utility type, and can be extended if they continue to pay maintenance fees on it. Utility is more common (20 years) because it allows for design revisions. Means a scope marked 1960 could be 1980 or even later with that patent date.
Redfield was sold, and sold and sold again. I did a lot of research on-line to sell my last one about a year ago... this may not be the exact trail, but SB close. The Denver addy only takes original Redfield's to about the mid 90's when they were sold to Blount, who did not make any Redfield scopes. The Redfield name was sold again a few years later to Allied Tech, they did market some made by Leupold under that name. Then they sold to Meade who made none. Redfield was sold again, to Leupold who makes the present Redfield models.
The old Redfields I owned were outstanding top drawer scopes in their day IMO, mine were all pre "widefield" I think (or at least I never owned a widefield). Their mount design as copied by Leupold and other makers attesting to them being a leader in the business. Last one I had I just sold about a year ago, a 12X target dot model with side focus that was as good or better than anything similar even today in the 40MM objective class. It was very long, typical of older models of "T" scopes back then by other makers as well. Still clear as a bell, all turrets and reticle's still worked like new, and it had been on some fairly big kickers. Unfortunately the life time warranty of the Denver made Redfields is useless, nobody warrants them anymore. So if yours fails it becomes a wall hanger. Doubt it will though, their old scopes are very well made IMO.
FWIW
