I agree that the timeline seems wrong. Made much later, IMO. I don't have an answer, but something to consider --

Caesars Tahoe had some chips in 3 colors, most likely made for home game sale, never for use at the casino.
They had a "Hats" (but no cane) mold, with circular injection marks within a few of the hats.
As I recall they were lighter weight than actual H&C clay chips.

You can see them on the Chipguide website at: http://www.themogh.org/cg_chip2.php?id=NVLTCT
Look for them under the "Odds & Ends" section.

While your white Roulette "C" chips have a Hat WITH CANE mold, it could be a later variation from the another knock-off manufacturer like the Caesars Tahoe chips above. Bottom line, I don't think yours are genuine H&C chips from Paulson or C&J. Just my opinion. I'd bet on generics made for the home market ... though anything is possible.