Tecate wiseco piston 439 same as 431 ????

[nd4speed]

Ok Wiseco 439 series piston is for all Tecates 3 and 1978-86 KX250.

Wiseco 431 is for 81-84 ATC 250R Honda.

I open my 1986 KX250 top end and find a 431 piston and a needle falls out of the wrist pin bearing.

Ok I think this is the wrong piston cause its is all sloppy and not machined to be near the small rod end.

Order a NOS (old wiseco box) 439 and inside I find the same 431.

This can't be a coincidence. I realize they machined stops for the bearing but its so sloppy.

So is this 431 piston correct?

Is the 81-84 ATC 250R piston the same as the Tecate piston or are they machined different (windows, ect.)?