Rear drum part number for a 72 Duster?

The stock rear drums are the bell style...no part number needed, you can spot those from outer space. The ones you get from the parts store are not going to look anything like the stock drum, but they will fit. If you can find a good used one, I would go in that direction rather than deal with the mystery metal in todays parts. BTW, check for the actual availability on that drum. Many places list them, but over the last year or so inventory has dried up. I sell literally every SBP 10" drum I come across just as fast as I offer them for sale.