The Superformance number is stamped on a plate which is attached to the passenger side of the firewall. The plate is black. Your SPF is only 11 away from mine. The plate in the picture below is just above the carb. I'm surprised that you missed it, or that someone removed it!
I'm sure that the same number is on the frame, but I never went looking for it!
PS _ Don't believe Terry ... he has trouble seeing the differences between a Cobra and an Olds 442 ... maybe we are long lost brothers