Standard, fixed Glock sights will work just fine if you simply turn 'em around and re mount them so the white points toward the front of the muzzle. This will give you a cheap, all black, sight picture. I don't think it works with the factory adjustable rear, however. You certainly should be able to use flat black paint and black the dots and U out at least. I, too, prefer all black sights with no dots.
My guess is that the vendor did not want to take a chance on screwing the slide up and having to "eat" it for a few bucks profit on the sights and install. It would seem to me that the alloy slide would require some careful tightening in a vice, etc. and while perfectly sufficient for its' purpose of firing the .22LR, I can see where it might be a little tricky to work with. I have NOT heard of any major problems with the AA product however.
Good luck!