Correction, not a 1902 Sporting, but a late 1900.
BluesBear,
According to my research & the Blue Book of Gun Values, the pistol I have, serial number 4141, is a Colt Model 1900, not a 1902 Sporting. The Model of 1900 ended with serial number 4274 & the Model of 1902 started with serial number 4275. According to Spencer Hoglund, whom I contacted about this pistol, he stated, "...as far as the hammer goes, Colt produced 1900's and 1902's with 3 hammers. Some were the high spur hammers, some were round (bobbed) hammers, and some were more normal looking (the shape is somewhere in between). The high spur hammers were found on the 1900's and the early 1902's, so it is expected to find round hammers on the later guns. The round hammer was not used for long, and after the round hammer Colt went to the standard shaped hammer seen on the majority of '02s. This hammer is an earlier version of the standard 1911 hammer. As far as the serrations go, John Browning moved them several times to find the optimal location. He feared that placing them in the rear would cause the gun to rock backwards in your hand and be pointing right in your face. This is why he tried them towards the front of the slide. What he found here is that you are more likely to shoot yourself in the hand, so he eventually moved them back. I would recommend the book by Douglas Sheldon called the COLT 38 AUTOMATICS. Best of luck and I hope this helps..." This explains the rounded hammer & front slide serrations that certainly make this particular pistol appear to be a 1902 Sporting, but the serial number confirms it is a late 1900.
1456 pistols were produced in 1900, 1694 pistols were produced in 1901, & 1124 pistols were produced in 1902. Total serial number range for the Model 1900 is 1 - 4274. Also, the Colt Model 1902 Sporting had "September 9, 1902" added under the legend ""Browning's Patent"/ Pat'd April 20, 1897" on the left-hand side of the slide, which mine does not have.
BroGeo