It's a tiny weeny difference, it could just be for manufacturing variance. After all they are stamped up afterwards, it's not in the casting.
Cyliners are marked up A, B or C
Pistons are B, D and no mark.

I can't remember or find a link to what matches what. Somone will know and it'll be here anyway and it's better to measure the clearance anyway.

Jap4 just list what Tyga list.
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