Piston and cylinder look every bit serviceable to me .
I'd clean the piston , including the ring landings . If there's decent compression , I'd run with it . Maybe just a light hone . Be sure the rings move as they should in each landing .
If you do get new rings , definitely hone the cylinder .
Once together , I'd definitely clean the outside of the top end . There's enough crap built up on the fins to advance an over heat problem .