Bill - Unfortunately the answer is yes.
Original 1971 Chevrolet 350 cam gears (36 tooth) for all applications is listed as GM# 3896960 according to the below extract (1st pic) from an October 1970 Chevy Master Parts Book covering the 1971 model year.
A web check came up with an NOS GM 3896960 Camshaft Timing Gear being offered on evilbay. The 2nd and 3rd pics below are screengrabs from that ad showing the overall gear and close up with the specified part number shown.
Looks like it's time to fully open up Jack's 350.
PS - I found that Chevy also used a nylon type cam gear even in similar year Big Blocks under GM# 3856356.
