The 6001 is the generic number that is supposed to indicate the OD, ID, and thickness. The letters are supposed to indicate whether it's shielded, one or both sides, and what the shielding material is. The other number you gave is probably B & D's part number which would be necessary for them. Like you say, you have to wait until it is apart until you know what the generic number is. I've heard that there are only 3 or 4 bearing makers in the world that actually make the rollers or balls. I also doubt that B & D makes the brushes. Whether they were specially made for them is hard to say. If B & D ordered enough of them they could be but if they weren't going to need enough to be able to do that then they would have picked an off the shelf one that was also being used elsewhere. I had an alternator go on me once on a Toyota car (the brushes I think it was) and I was in Vancouver at the time. I couldn't get the parts from a dealer without a wait but a little hole in the wall electrical shop had a look at them and he said he was pretty sure he had some like it and 4 hours later I was on the road again. Who knows what the ones he had were meant for.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.