Rick,
The rule of thumb for engine builders is 10 psi for every 1,000 rpm the engine is made to turn. If the egine will go to 6,000 rpm your pressure should be 60psi. If your engine will never see the high side of 4,000 rpm than 40 psi is fine.
As a builder I would remove the front timeing cover and check to be sure all of the lifter galley plugs are still in place. If one pops out the pressure will drop but because of the engine oiling system you will still show pressure and the lifters will not make noise at lower rpm.
You could also drop the pan and see if anything is in it, say like a galley plug. We use the Melling HV/HP pumps in our engines and have never had a new engine with
oil pressure that low.
Be on the safe side and check it. You really do not want to rebuild it due to lack of pressure at speed.