Ok, I went thru some more of the parts I was given with my 70 W and found two GM one piece rotors (used). All the parts I was given were for A-body Oldsmobiles, so I'm going on the assumption that these are useable, if they measure ok, for my car. I can't find any part numbers on them but one has "GM23" cast in between two of the studs and the other has "GM17" cast in it. They look identical, so I'm not sure what the GM23 and GM17 are trying to tell me..........but hopefully one of you will know.
Any ideas?

thanks,
bob