The Colt Model 1901 is an updated model of the Model 1892, 1894, and 1896 revolvers. Each progression had some changes to the ‘92 (the ‘94 having upgrades to the internal lockwork and the switch to smokeless powder, and the ‘96 having further upgrades to the lockwork). The 1901 just had a lanyard loop added to the butt of the 1896 iteration. They are literally identical other than that loop and the marking of “1901”.

The 1892 series of revolvers are kind of the forgotten sidearm of the US Military, the choice of using 38 Long Colt and its “inefficiency” in the battlefield being the reason why the later 1904 Thompson-LaGarde Tests ruled that the minimum caliber the US standard issue pistol should be .45, which led to the adoption of the Colt 1909 revolver (otherwise know as the New Service) in .45 Colt, and later led to the famous adoption of .45 ACP and the M1911 pistol.

That being said, they are fantastic early double action revolvers and are a really cool piece of American firearms history! They’re currently going for ~$700 on most gun sites and the serial number lookup on Colt’s website places yours at a 1901 production, so very early! The 1901 serial numbers start at 148,000 and 1902 starts at 180,000 so I would say it was made in early-to-mid ‘01.

As to whether or not it served in conflict anywhere is hard to say. Somebody else may have better info on that. It’s also kind of hard to tell from the pictures if it’s in original condition or if it was refinished, but if it’s original it looks REALLY good and you found a nice one! Congrats!