All serial numbers numbers match, it has pat dates sept 19 1871, July 2 -72, Jan 19 -75. Followed Buy US on the side , 
on the barrel marked colt's pt. F, A. MFG Co Hartford Connecticut USA

With the addition of the "U.S." stamp following the patent dates, The  revolver is officially identified as a highly coveted U.S. Army Contract Cavalry Model manufactured in 1878
According to historical records from the NRA Musemums serializations data base  Colt began production in 1878 with serial number 41000 and ended the year around 49000

Because it has a military  US pedigree and all the numbers match, the 5.5-inch barrel tells a fascinating historical story. The U.S. military only accepted 7.5-inch barrels in 1878. There are two historical reasons your gun now measures 5.5 inches:

Scenario 1: A Rare "All-Matching" U.S. Artillery Alteration
Between 1895 and 1903, the U.S. Government recalled thousands of 1870s Cavalry revolvers to shorten the barrels to 5.5 inches for the Spanish-American and Philippine-American Wars.

• During this refurbishment process, workers threw components into large parts bins, meaning 98% of "Artillery" Colts have mismatched numbers
• If The gun was shortened by the government but somehow kept its original matching frame, trigger guard, and backstrap, you have a rare "matching-frame" Artillery model , which commands a significant premium over mixed-number versions

Scenario 2: A Period Frontier Modification of a U.S. Gun
After serving in the Indian Wars, many U.S. Cavalry Colts were sold as surplus or kept by discharging soldiers. Out on the civilian frontier, cowboys and lawmen heavily favored the shorter 5.5-inch length for an easier draw. It is highly possible a historic gunsmith cleanly cut down your gun's original 7.5-inch military barrel while leaving the matching frame intact.
Valued 4,500  to 8000 
Appears to be in good shape. The barrel measures approx 5.5 inches. In total measures approx 12h x 3w x 6d inches. See pics. E-5360