Howdy History Fan,
You have a 2nd Model LARGE FRAME HAMMERLESS revolver made to handle .38 S&W Cartridges loaded with SMOKELESS powder, as it was made sometime after 1905. Based upon the serial number, it is either a 2nd Variation (1907 - 09) or a 3d Var. (1910 - 13). The serial number falls right in the seam for the end of the 2nd and the beginning of the 3rd. If you supply the stamping on the top of the barrel rib, EXACTLY as it, I can tell you exactly which variation you have - but indications are it was made in late 1909 or early 1910. Hint: a 3rd Var. will have only one patent date: Oct. 8th 1895. While the 2nd will have: April 2nd, 1895 and April 7th, 1898.
The change has to do with improvements made to the auto ejecting mechanism and the barrel latch.