Rear Brake drums 1966
 

I am accumulating the correct parts for my 66 Olds 442 W30. The rear brake drums are not OE and I need to locate two drums.
Were brake drums date coded?
My research tells me I need the stamped steel drums with the flange as opposed to the cast finned style. Some car lines may have used a plain cast drum as well as found on 67 Camaros.
Were the same stamped steel ones used on the Other GM A body lines.
Any leads on info or sources is greatly appreciated.

Paul Martin