Looking at the early UMC price lists on the International Ammunition web site I see 1869 and early 1870s show 10- & 12-gauge brass shells. By 1878 they show 8- to 14-gauge brass shells. The 1880 price list shows a wider array of brass shells including No. 11 & 15 and they mention A & B shells along with the addition of paper shells.
1880 UMC Catalogue.png
In the 1882 UMC catalog they only list No. 11 B shells --
1882 shotshells.jpg
By the 1884 UMC catalog the No. 11 shells are gone --
1884 shotshells.jpg
Hybrid Mode