Do I need a cylinder reserve or a rebore

1976 KZ900 Do I need a resleeve or a bore
I've owned this bike for 45 years. Previous owner abused it. It ran reasonably for about 25 years. It sat for the last 20 years.  Decided to get it ready to sell. Checked compression. All cylinders between 60-90 psi. About 10 -20 psi improvement with oil in cylinders. All shim clearance within specs. Disassembled engine. Bore diameter 69.63 mm to 69.84mm with greater than 0.05 mm out of round for all cylinders. Gap with rings loosely installed in cylinder within specs. Cylinder marked 900cc.
Question: Clymer states I am way out of spec for a 900cc and barely in spec for a 77 1000cc. Has this bike been resleeved or simply bored out? Will I need a resleeve or a re bore?
 

It's been rebored a few times and it sounds like you are on the max stock oversize.
The 900 liner can comfortably go to 70mm (1015cc ) which is max stock oversize and then up to 70.5mm (1030cc) and then 71mm (1045cc ) which leaves the liner a little on the thin side.

Thanks. I need to find a machine shop here in San Antonio. Clymer recommends buying the pistons prior to a rebore so that any variations between pistons can be adjusted during the boring process. Should I purchase 70mm pistons or something else?