If you are having O2 deco tank you should probably be closer to 2400psi (or less) in the tank due to issues with scuba regs. O2 reg I have is 100% O2 compatible for pressures up to 2400psi. (Many people forget to read the details in the reg and many manufacturers leave that important info out I guess.)
If one has an adapter for scuba tank to medical regulator and the dive is with 100% O2 deco chances are that at least some of that O2 gas is still available from various members of the dive team.
DiveRite 100% O2 reg is good up to 3000 psi. I have a couple Mares M12's that came from the factory ready for 100% O2 that I believ are good to 3000 also. I need to double check the latter, didn't notice any psi restrictions in the manual but will double check.