I don't see why not. They will just bead blast or sand blast it then blue it. The matte finish Remington uses is not that tough to get off. Heck most of it comes off within a couple of years of use anyway. I hate the matte finish that Rem uses, it rust like no other. One thing to think about though is the expense. It would pay to search the net and find a 21 inch barrel to fit your needs instead of converting. A good blue job can cost a bunch of money, more than the price of a new barrel.