i used to run a little speed shop was a Jobber with Gratiot Auto Supply amongst others sold a lot of those around 1965 I would guess about 64 to 69 or 70 on the period
Some manufacturers (Cragar especially) cast a date code of sorts into the back of the wheels. Some of them took a little while to decipher but it's worth taking a look.
Rocketts had a kinda sharp edge ran down the middle of the spoke first new set of wheels I ever bought 1970 at rinks department store
http://www.jalopyjournal.com/forum/album.php?albumid=27430&pictureid=308641 http://www.jalopyjournal.com/forum/album.php?albumid=27430&pictureid=308642 Heres the backside and center cap. This is the only cap with a logo.