Looks like a .38 Hand Ejector (Military & Police) Model of 1905. Because of the presence of a trigger rebound slide stud, it is at least a first change, but could also be second. That seems to be a 6.5-inch barrel, which means it is not a third or fourth change. So it probably dates from 1907-1909, around there.
I picked up a 6.5 inch 1905/First recently. Haven't shot it yet, but took a few pics to see if it would make a new avatar.
EDITED TO ADD: Mike's right about the medallion grips. If they are original, the gun is at least a year or two later than I thought it might be.