First, I agree with Jerry - you are probably all right.
However, a reading of 15 psi oil pressure from a 261 is low. The pressure relief setting (a spring, I think) for this engine in between 30-45 psi.
I ran my "high-pressure" 235 at 5 psi for a long time but it finally got so low at idle that I would get a 0 psi reading.
If the engine drives OK, just keep an eye on the oil pressure. Also, consider switching to a higher viscosity oil (I used 20W50 with my worn out 235).
