If that's the serial number, it dates from 1907. They are one of the the largest Colt revolvers made in that era. They are identical to the Colt Model of 1917 except the 1917 was chambered for the .45 ACP cartridge.
The New Service was made in .45 Colt, .38-40, .44-40, .38 Special, .357 Magnum, .445 Webley and some other calibers.