Between the C3 Cougar Mag. NOS X, and the C4 Cougar Mag. NOS X? Specs appear to be the same?

Also, why the speed loss between it and the Slayer NOS X? The C3 Cougar Mag. NOS X has 1/2" less BH, and 1" less length, same cams. Yet the Slayer NOS X IBO's at 335, wherease the C3 Cougar Mag. NOS X is only 320. Was Martin more honest in 2005, and posted IBO speeds an average shooter/tuner could obtain?

Alec