Welcome Aboard, it's good to see you here.
Rrumbler tells it straight. 5 psi at idle when hot is low but not 5 alarm fire low.. I'd replace the motor oil and filter ( I prefer synthetic motor oil ) and he suggests replacing the oil psi gauge. We don't know if the current gauge in place is mechanical or electrical, but I would suggest getting a mechanical test gauge that replaces the unit in place on a temporary basis. Just to verify the validity of the readings your getting now.

He is also correct on the rings topic. And I'd say if it can make even 15 to 20 pounds of oil pressure, I wouldn't worry about it for now. Use the motor as is and feel the car out and see what other things will need repair / replacing / changing etc..

This will help you make a plan without any surprises (hopefully) and have a car you can enjoy.