Wondering what the difference is between adm ae86 calipers and jdm ae86 calipers?

Reason is I have adm shit on my ke70 atm, and have what is supposed to be a pair of jdm calipers in the shed. Though they look to be exact same, all the numbers on them are the same too except one, I think on adm its 71, on 'jdm' its 81.

These supposed jdm calipers are on jdm vented rotors and dont seem to fit properly, grinding away the outer edge of the rotor.

Any help is apprteciated...

Cheers, Ben.