If this is the only way to distinguish between FM1 and FM2 then perhaps a lesson in radio vasectomy is in order.
Steve, will you please explain the dos and don'ts of prying into one of these radios? This is a much smaller scale but when I was young and stupid I opened the back of a TV thinking that simply unplugging the unit would cut the power. I touched something inside with a screw driver and it knocked me out. My hand was the ground and the carpet underneath started on fire. Electronics to this day scare the boigie's out of me, think that's a word.
Will you also post pics of the transistor you are referring to.