Yes, you are right. The cam and other factors will affect the PSI. The main thing is if all the reading are similar, with no cylinder way lower than the others. Your test looks good.
I'm looking at my 1972 B110 parts catalog. It lists two types of pistons: All ("reg gas") and GX-H ("high gas"). It also lists two long blocks:
10001-H2350 GX high gas
10001-H2356 GX reg gas
It only lists one type of GX head and camshaft, so presumably the difference is in the pistons. The
Datsun 1200 group 1 FIA recognition amendment doc lists 10.0:1 and 29.1cc combustion chamber but the earlier engine (non-GX?) had 36.6cc combustion chamber.