Yeah, I knew they did that with some stuff. I dealt with one of those 6"disc/36"belt combo sanders recently (a Craftsman) and discovered that there were about twenty others. Usually, there'd be a minor difference in the plastic bezels or something, and sometimes a few part changes, but there were a couple like you say that were exactly the same. It actually helped, as I ended up needing something for it that Craftsman no longer had (Grizzly did).
I saw a couple 3612 knock-offs when I looked, but they had that cheap, fake look with the Harbor Freight blue plastic and the bodies were slightly different. This thing has that weird aqua blue fiberglass looking plastic like a Makita and decent looking casting for the aluminum. I'm guessing the same machines spit this thing out.
- Thanks for the tip on that 1900B too. I use one here and wasn't aware that it had family. That's one of a couple of mine that I recently restored with all new bearings,etc., so I hopefully won't need to go back in it for a while.