In sequential order:
en70714a/en72841a
Oversize - not unless you want to rebore
Rebuild - No, top end only most likely. But with bearings its all relative - I just tore down a later model with bearings which felt average, but would knock over 1/2 throttle. I would suggest squirting a fair bit of thin oil in them, swish around and then tip back out to check the colour. If brown crusty gunk comes out, you have a problem.
You were very lucky regarding blade plate - last week I (110+kg) was swinging on a 600mm breaker bar + another 300mm of victa handle and even with my heavy frame it wouldn't come off with heat or soaking in penetrene. The blade carrier looked like a pretzel by the time it came off.
And that was 10 year new model than yours
