Good call, this is what I found on velo-retro.com
1963 - In October the Record rear derailleur (chrome plated bronze) is introduced. This has a revised cage shape with the pivot behind and closer to the jockey pulley and center punched rivets. The word "Record" is added to the hub barrels. Thicker heads on seat post adjusting bolts. Low cost "Campagnolo" model derailleur introduced (black oxide finish with the word "CAMPAGNOLO" on body), an economy version of the Gran Sport derailleur.
EXCEPT, is that a black oxide finish on the derailleur? I doesn't look like it to me but what do I know.