Can anybody answer this one? A guy has asked me a question I don't know the answer to. He has picked up a MIM '50s Classic body in a "Partscaster" build, are the string spacings/trem dimensions the same as a US Vintage trem? I know the standard MIMs are different but he seems to reckon the MIM Classic is the same as the MIA? Never having had my hands on a MIM Classic I just don't know.

Yes, the MIM Classic/Deluxe bridge has the same screw spacing and string spacing as the American Vintage Reissue bridge. They aren't completely identical but all the parts are interchangeable -- US saddles and blocks fit on the MIM Classic bridge (the MIM bridge has a full size zinc block instead of steel).

The AVRI bridge (or any of the aftermarket US-spec bridges) fits the MIM Classic/Deluxe bodies with no mods.

Thanks for that strayedstrater.