Given 8500 ft, 130's is not so bad.  mine run in the 150's at around 300 ft above sea level. 

However, the diff between each side sounds weird.  I do not know why other than maybe one head/gasket is someway different from the other.   It would be strange for rings to do that.

From one airplane mechanic to another I agree with TKO. I doubt that your airplane ever had even compression numbers. If it did your gage was broken. The numbers on airplanes have always been more reserved than cars. Yours are definitely within those limits. In the past I've experienced compression leaks around the sparkplug seal that cause a miss. Motorcraft plugs fixed that issue but that was with iron heads with tapered plug seats. I'm getting that miss again now that I have aluminum heads that require plugs with gaskets. I haven't found a plug or anything else has fixed it yet. There is a tool out there that we used to use at the car shop that could find a miss in a cylinder. It could tell if it was a wire or plug or low compression but I can't remember what it was called. It was also hooked up to a device that could read how rich of lean your mixture was when you stuck the probe up the tail pipes. The boat shop I worked at had a portable one.