For model year 1994, the main changes to the rear derailleur range were:
- Record, Chorus, Athena and Veloce got a makeover.
- Stratos was introduced as a new, even lower-end road group. Stratos only lasted one year.
- Record OR got a makeover, but lost the long cage version. It's possible that the long cage version had sold out and Campagnolo did not want to manufacture any more.
- Record OR was the only mountain bike groupset left standing, as Icarus and Centaur were ruthlessly killed off.
So I think that the rear derailleur range might have been as follows:
- Campagnolo Record (RD-21RE)*
- Campagnolo Chorus (RD-21CH)*
- Campagnolo Athena (RD-21AT)*
- Campagnolo Veloce (RD-11VL)*
- Campagnolo Stratos (RD-01ST)*
Mountain bike 8-speed
- Campagnolo Record OR (RD-21OR)*
- Campagnolo Record OR (RD-22OR)*
* New for model year 1994
From some time around 1992 the part numbers were made up as follows:
- 'RD' for 'rear derailleur' - which was not particularly Italian.
- A dash for good measure
- A number to indicate the 'generation' of the model. So, for example, generation '2' replaced generation '1', etc...
- A number to indicate the cage length. So '1' indicated short, '2' indicated medium and '3' indicated long. etc...
- Two letters that indicated the model/group name. So, for example, 'RE' meant Record.
These images come from a slightly tacky pdf downloaded from the Campagnolo web site some years ago. The rear derailleurs are featured from page 14 to page 17.