Re: 1907 Colt da 38 revolver?
That gun has the cylinder stop notches, so it is not the Model 1889. It is one of the series* of Army-Navy revolvers made both for the military in .38 Long Colt and for civilian sale in .38 and .41 calibers. That gun is a civilian model.
Value depends, as always, on the amount of original finish and, for this gun especially, on functionality. The mechanism is fragile and many have broken or worn parts; few parts are available and few gunsmiths know how to work on them.
*Models 1892, 1894, 1895, 1896 1901, and 1905, the last made for the USMC. The models are basically the same except for internal differences, a smaller butt on the civilian models and the round butt on the USMC model.