You sort of take your chances on a real antique. The theory is that the cylinder or barrel OR SOMETHING could have unseen hairline cracks, etc so just hang it on the wall.
You want to make certain the chamber lines up with the barrel, all the chambers. To do this you need a range rod that is put in the muzzle and run down to the chamber, if it "bumps" the chamber- the gun doesn't index properly and it will spit lead or blow up- depending on the degree of the problem.
The gap between the cylinder and the barrel shouldn't have a lot of play. This can be adjusted by the wedge to a minor degree.
If you remove the wood grips the backstrap can be clamped into a support of some sort and you can attach a string to the trigger and test fire from a safe position. There are a variety of books on single action colts and the mechanism on the percussion guns is basically the same as the cartridge guns.
Good luck. Be Careful, and THINK.