Yep. Barrels are sold all the time. I usually see them around the 75 to 80 dollar mark. However, the barrel and receiver are one piece so it will need to go through an FFL.
Or private sale if you do it within state in most states.
If you don't get any offers here, contact one of the businesses Timothy posted. They do the barrel swaps, and I'd bet they have a supply. I know MB has his vampire red set up, so he might even have an old one ... It might even come with an autograph