The reason why it's difficult to estimate these specific prices is because they found a Colt 1873 revolver and a Smith & Wesson No. 3 revolver at the bottom of the box.
On the bodies of these two guns, Leonard Ethan found the signatures of St. Denis Kidd and Butch Cassidy. Apparently, before they left for a faraway place, they hid their guns that they couldn't take with them here.
Because both pistols were carefully wrapped with several layers of wax paper after being covered in thick butter, and stored in a dry and cool place, the firearms are in excellent condition.
At least according to Barry's judgment, once they got back, all they had to do was remove the butter from these guns and perform simple maintenance, and they could be used directly for target shooting.
Considering these two are somewhat famous figures from the Old West era, it's an unknown how much their firearms could sell for. If someone truly liked them, it's not impossible for them to spend a fortune.