82 Kz1100 Piston parts number

Hey folks I'm looking around for a set of OEM std size pistons with no luck.
I found 13001-1054 listed on eBay for 1981-1983 GPZ1100-KZ1100 Pistons. for sale are they the same as the stander piston?
I know the stander part number is 13001-1118. can any one please share some info.
Thank you

I think, but double check me on this, that the GPZ pistons have a different size piston pin. I think the KZ1100 pin is 17mm and the GPZ is 18mm. So they won't work.

I did see one NOS piston on ebay this morning but only one.

Do they have to be new or could you live with used?