Wow, that late. I would have thought it was older. Was it a TriPacer that was converted? I don't have a lot of data on the PA-20/22 so I can not claim to be an expert. I thought all the round window versions were 135 HP but that just proves my lack of knowledge on the subject. I do know that the PA-20/22 was built for a very long time. It was built into the mid 60's and a bunch were made during the run.
I flew a 135 HP during my early airport bum period. It had coordinated aileron/rudder and came down like a stone. The guy that owned it took great pains to scare the hell out of me with steep aproaches into very short fields. Note I said fields, not airports. She always arrived like a lady but the last 30 seconds were something else.