I agree with OLUT on the only two bore sizes. I have acquired quite a few for family and friends over the years.
The first production run of the .50 rifles had a 7/8" barrel, which handled well, and made a reasonably authentic, slim rifle. They were very well shaped and finished out of the box.
Dixie / maker became concerned with liability, and changed to a 15/16" barrel, maybe safer but definitely heavier. And the wood was heavier, a hump at tang and extra wood, benefited from a trim. Bob