I don't think Mark has a catalog, but back in January, he had an end-of-year sale to thin out his inventory - 10-20% off. He listed a page and 3/4 of rifle barrels and a page and 1/4 of pistol barrels, approximately 40 barrels per page or close to 120 barrels total. First come, first served. I bought two rifle barrels and two pistol barrels.
He had a number of octagon to round pistol barrels listed. Some were straight octagon to round and some were tapered octagon to round. Some had wedding bands, some didn't. Some came with breech plug installed.
So Smith, I believe the answer is yes. My suggestion is give him a call and see what he can do for you. You definitely want to get on his mailing list in case he has another one of these sales.