Yes, there are apprx 35 different part numbers used for plastic cam (via Jon Hargrove at the Carb Shop).
There are several configurations, different number and size of the "steps", but they all function in the same manner if notched for the pin far as I know.
It is difficult, if not near impossible to find one that isn't cracked, but that doesn't seem to hurt function as long as they are intact.
I have about a dozen 1967 cores here that are "junk", I may have a few cams on them that are useable and decent shape......Cliff