Welcome to CSC!
Yes, a 1972 is a "Potter" hull. Here is a link to production numbers for all Seacraft models built from 1968 to 1980:
http://www.classicseacraft.com/broch...production.pdf
You can probably assume that the original 35 year old transom will need to be rebuilt in the near future so factor that into your price. Both the 20CC and 20 Seafari are great mult- purpose boats offering one of the finest rides available on the water.
Best of luck!