The Model 1909 is a Colt New Service. The story is interesting. In 1908-09, Army Ordnance became concerned with the seemingly endless testing involved in selecting an automatic pistol and decided to buy a new revolver to replace the old .38 revolver that had failed so famously in the Philippines. So they decided to simply buy some 18,000 of the New Service, have Colt put Army markings on the butt along with the serial number (which at that time Colt was putting on the crane and on the frame under the crane), install plain wood grips and give the Army what it wanted. The Navy and Marine Corps later purchased Model 1909's with their own markings, 1000 by the Navy, 1300 by the USMC.
The Model 1909 is considered an interim gun, and it was superseded by the Model 1911 pistol after only two years. But in fact, no one knew, in 1909, when the pistol would be adopted, and the 1909 was fully intended for the long haul if necessary. Colt chambered the guns for .45 Colt. After Army testing, it was found that the small rim of the .45 Colt allowed the rims to jump the extractor, hanging up the gun. The result was that the Army had its own ammunition made at Frankford Arsenal, with larger rims. That ammunition is the Cartridge, Revolver, Caliber .45, Ball, Model 1909; it was the only cartridge issued with the Model 1909 revolver. The old .45 Army cartridge could be fired in the Model 1909 but was long obsolete; so could the .45 Colt, but the Army had not issued that cartridge for 35 years.
R.A.C. (not G) stands for Rinaldo A. Carr, a Springfield Armory civilian sub-inspector, assigned to Colt. F. B. is Major Frank Baker, the Army inspector at Colt. Later guns have W.G.P. for Maj. Walter G. Penfield, who replaced Baker.
The Model 1909 was never made to accept half-moon clips, since it was never used with the .45 ACP cartridge, only with the Model 1909 cartridge.
The military guns were made with the standard Colt high polish blue finish of the day; they did not originally have a dull finish, though some were refinished in the WWI era with a dull blue. They were issued through WWI to troops in the U.S. AFAIK, none were sent overseas due to the ammunition difference.
Value, in that condition (if it is original - the pictures are not good enough to be sure) could run over $2000 for the Army model, $1000 more for the Navy or USMC model. If reblued, those figures will be reduced by almost half.
Jim