I just acquired an old Campagnolo Gran Sport rear derailleur that is different from others that I have seen. This particular derailleur does not have a barrel adjuster on it. And the hole where one would think a barrel adjuster should go is not threaded. Obviously the cable housing end sits down in this hole.
I have another old Campagnolo Gran Sport rear derailleur that does have a barrel adjuster that is hexagonal in shape that thread goes into the threaded hole.
My question is: Approximately what year was the GS derailleur without the barrel adjuster made?
The only other visual differences between these two derailleurs are that the first one is stamped: PATENT CAMPAGNOLO DA14 A 26 DENTI in standard lettering on the rear pivot plate. The surface chrome is also somewhat "cruder" looking than the second one. The second GS derailleur (with hex adjuster) has the identical stamping on its rear pivot plate; the only difference being that the lettering is the "open C" and "flat G" type.
Logic tells me that the barrel adjuster was a feature that was added later on to improve the product.
Any input that anyone has would be greatly appreciated.
A gloomy day in Palo Alto, CA
Ted E. Baer