I think I'll get the oil changed tomorrow and have the shop check out.
If it never drops below 20 psi at hot idle and rises with RPM to the 30 to 40 range ( at operating temperature) then it's perfectly normal, and actually what I would consider very good for a near 200,000 mile motor. I personally use Rotella T6, which is an HD 5W40 synthetic oil. I get 20 psi hot idle, 60+ cold idle, and 40+ above 1000 RPM at op temp. My motor has 267,000 on it and has only a slight lifter tap in the first few minutes of operation.
If you would like a shop to look it over for peace of mind, then definitely do so, but if it is in the ranges I mentioned you have nothing to fear.