DeeJ..genuine piston set part# 12104-46820-100 This is listed a piston set and should include rings but double check beforehand. (rings alone # 12140-28630) The local oz/nz dealers may not show the number for the 'set' as I had that problem with the 400..they had no reference to such numbers and the system would not let them order it. Maybe the US had slightly different marketing for spares..dunno
You'll have to use the 77 RM125B fiche as the later models only showed up to 0.50mm
Both items showing available ex Alpha-sports so check your dealer first.
Failing that I think I have a spare 1mm over piston here but I'd have to double check I don't need it cause it's been so long since I played with the 125 I forget where I was up to
