Not that long ago I picked up a bundle of stuff from what seemed like an ex-IBM employee (there was a bunch of documents and letters from the company mixed in) and in the pile was a Model 001 mouse. I didn't think much of it, as I've never even seen a Personal System/2 before let alone owned one, however when looking for photos of others to compare I noticed that my mouse seems a bit different.

For starters, the plastic has no texture, it's flat and semi-glossy beige whereas all the ones I see online have a slight roughness to them. Secondly the label underneath has a few small differences - there is no FCC ID or UL certification number (just empty spaces where they should be), and others seem to have K-L or L-L listed above the serial number but that is also blank here. And finally, the buttons seem to be just slightly more recessed into the housing (they're almost totally flat with it).

Does anyone know what is up with this, is it like a really early revision, or a late cost cutting one, or just a UK variant or something?