the whole i believe is more like 5/8" and only 2 holes on side but perhaps it used the 2 holes for the current bracket too? I never took it apart to see what it looks like under the bracket... maybe tomorrow i will.
Sorry if I wasn't clear enough. The three drums are certainly close enough to have been shipped from the factory to fill one order for a kit. The snare is probably an earlier one which has been added later. But a Supraphonic is the catalog correct snare for the Jazzette kit. Maybe somebody sold the rest of the kit and kept the Supra, and later on a different person brought a different Supra together with the kit. About those holes...sounds like it might have been drilled for a Pearl (or similar) mount, but that's hard to say for sure without knowing the diameter of the hole. The Pearl pipe is 7/8" diameter, but the Pearl mount uses 3 screws as far as I can see (I'm looking at a couple in the next room). I don't think it would be a Ludwig mount. Something else...