Been to the battlefield a couple times, never gave it much thought that it was special ordered. Too hot to do much today, was reading a very large PDF file on the results of the excavation done after the fire there back in the 1980's that briefly mentions his rolling block.

This is an old report, very large report, around page 100 it gets into the guns used there.
http://www.npshistory.com/seri...gy/mwac/tech/124.pdf

Thank you for posting this.
As a side note:
George Armstrong Custer’s Sharps Model 1853 sporting Rifle .44 caliber serial number 21130 ca. 1855 is on display in the Buffalo Bill Center of the West in Cody, Wyoming

The attached note says:
Both the Sharps and the Rolling Block next to it were sporting arms that belonged to General George Armstrong Custer. His widow Elizabeth gave these firearms to the Winchester Arms collection.

I took a photo of the Sharps but not the Rolling Block.

PC

The Remington Rolling Block was used by quite a few foreign militaries after the Civil War. The French even used them in WWI.