145 sounds fine. Typical compression on gas engines is 125 to 150 psi. You also want an even spread within 25 psi, such as yours. I never saw a compression gage that was really accurate to 3 psi! Also remove the spark plags and look at them. Excessive carbon or oil would be a warning flag. A good visual of the exterior for oil leaks etc should also confirm the reported o/h 40,000 miles ago.