Could be. My CIP chart lists the 9.3x64 as a 64,000PSI & 54,000 CUP ctg. = the same actual pressure - in this case.
The 7.62x54 is a 57,000 PSI (CIP) round, same as the various 57mm cases and 9.3x62mm.
I find this program and text very handy.

http://kwk.us/pressures.html