125-200cc Wr125 engine rebuild

I'm rebuilding my engine because the guy who owned it before me is an idiot. Originally it was just going to be a top end but on finding (and removing) chemical metal on the bottom of the crankcases I found that the PO had drilled a hole in the sump plug and made a complete mess of it somehow managing to punch 2 holes in the crankcases either side of the sump plug aswell.

So I just split the cases (which was ridiculously easy). Found a heap of swarf and bits of casing inside as expected.
Anyway the point of the thread, the crank slides in and out of the main bearings with ease. There is heat marks where the main sits on the flywheel side of the crank but it's nice and shiny on the clutch side of the crank (both sides slide in and out of the main easily). I tried putting the crank in the wrong way around to see if the mains either side had a slight ID difference.... Same story, slides easily.
Both bearings feel OK to spin, very slightly gritty but not notchy. Both have slight side to side movement on the inner race, but that is normal right?
It's the same story for every bearing on the bottom end....... The selector drum, input and output shaft bearings.
I think it's normal for the gearbox bearings to not need to be pressed in (right). It's the mains that concern me, as in, is it the main bearings worn or the part of the crank that the mains seat on?

Thanks

My guess is that someone turned the crank down a little to make splitting the cases easier. I had a kx250 like that. The crank bearings aren't too expensive, I'd just by a set and see if they fit any tighter.