Park 50 or 75 watt (?)

This guy is either a 50 or 75 watt, but I'm no electronics wizzard. It is in the best condition of any of my Park amps, and is dated 1969 on the tag board inside. Unfortunately, its tone is equally clean. I don't want to modify it at all because it is that perfect. Maybe some day I will get old and be in a blues band and record an album with it. The knobs are almost the same as the other 50-watt, but the pointer rings are black.