Its likely that the ring grooves are worn. You said in your 1st post that the piston was loose and that the top ring was loose in its groove ......most of this wear will be on the piston. If the rings were tight in their grooves then you probly could re-ring the motor but if they are loose not only will they hammer up and down in their grooves as the piston changes direction but they can also twist and they will never seal properly. All of this will cause accelerated wear and loss of power. If the bores are not to bad you maybe able to fit new pistons and rings be OK , hell I even fitted good-ish used pistons ( new rings ) into an old 50hp rude once and that went ok.
Another consideration is that while you can look into a port and see rings you cant verify that they aint broken somewhere you cant see.
The fact that this pot is down on compression ( 125 aint
that bad ) suggests there are issues .
You will have a much bigger smile on your face if this engine runs well as opposed to just goes sorta ok when you have finished the resto . If you have the time look around for parts , new or used ..... I dunno if you can get Chinese pistons for this engine but if you can Id go for that . I have fitted Chinese pistons into a few 2 strokes and are yet to be disappointed. Try Ebay for parts too .... you never know what will show up ( Loosely quotes Ric Harrison

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