TC is no more and S&W ain't gonna do anything for you to install an aftermarket barrel. You can polish the receiver or you can polish the barrel. Conventional wisdom dictates it's wiser to modify the barrel. It's also easier to accomplish. By "polish", I don't mean Flitz but with fine grit sandpaper. Preferably wet sanding, starting with 220grit, moving up to 400.
I would not do the heating and freezing method because you may want to remove it at some point. You can also end up cracking the aluminum receiver.