KP, I never forget a photo
Yes there were 2 early versions - one was a die cast version, the other looked like a sandcast version. The diecast version is the one that came out on Production bikes up to 26000 as far as I remember. You can see they look more solid. The diecast early version has '232' cast onto it. The other appears to have been produced as spares only. I have seen one in the flesh, and one on the CMSNL website. You can see very clearly on the inside, the finish is rough.
I think the later ones had a rubber sleeve inside, and possibly the inner sprocket guard. If it had the inner sprocket guard, when seen mounted on the bike, the cover has a visible recess to accept the inner sprocket guard.