The following guns were used in the film Silverado:
Single Action Army
The gun used mostly by just about everyone in the film is the Single Action Army revolver in the various barrel lengths and calibers. Many look to be in far too good condition to be the guns of Frontiersman and have obviously newer color case hardening as evident by the fact it isn't worn in the slightest. Back during that day, they used Cyanide to color case harden, unaware how unsafe it was to use. Today, more conventional and longer lasting methods are used. It is likely these guns were supplied by Aldo Uberti Inc., a major 19th century firearms company today. Do to the extreme frequence of these guns in the film, there are a lot of screenshots for them.
They're almost surely Ubertis, for the reason you said, but also look at the image of Bradley with his two SAAs. The bluing on the cylinder and the color of the frame look very identical to my dad's Uberti SAA clone.
Unknown Revolver
I hate uploading guns when I can't I.D. them but I just can't figure this one out. When Paden (Kevin Kline) runs into the gunshop to buy a gun to kill the man who stole his horse, his lack of money leaves him with a hunk of junk revolver which I cannot identify. The gun clearly has a swing open action (anachronistic to the time), but the gun is so shoddy, the cylinder falls off the action when opened. Anyone who has seen The Quick and the Dead would know that this scene was replicated somewhat in that film. (I'm ordering that movie off eBay to screencap as well. Leave this comment on so people know not to screen it.) -GM.
Winchester 1866 "Yellow Boy" (mocked up as Henry 1860)