I am going from memory but and I m sure someone will correct me. I think id be looking at the balancer and converter for balanced vs un balanced also i think each has a different bolt offset but i may be wrong about that. That determines balance if its forged vs cat Im not sure if the marks are on the flange I think they aren't the flange and snout are machined etc. so no forging marks etc. if the crank is out there is numbers on it etc.
Numbers are not on all cranks, DAMHIK! I sold a forged 383 crank to a friend and he took it in to the machine shop to have it checked out and it turned out to be a forged 440 crank I did not know I had! Cast cranks DO have numbers on them...