Are these a non-standard size? I've got a Bare Knuckle 58 pickup for my current P Bass build, but when I was putting some bits together earlier, the covers didn't fit through the hole in the pickguard. I checked the covers for a Creamery pickup from my JV Precision and they slotted straight in. I tested the BK against the other pickguards I've got and the casing only fit one out of the 6 I have. 'Fair enough', I think, 'I'll just swap the covers over', only this doesn't solve the issue as the BK pickup itself was too large to fit the smaller Creamery cases.
The difference between the two is only a millimetre or so, but it seemed odd that the BK only fit one pickguard; most of the ones I've got here are genuine Fenders. I know the response will be just to widen the hole in the pickguard I'm using, but it's anodised aluminium so I don't really want to do that. I may just move the pickup on as I'm not overly precious about using it, but I wanted to check that I'm not being dense and missing something.