I think something is broken there. The two piece top tang has overlapping sections, joined by a screw from the top. There is not supposed to be a gap between the sections of the tang. Either the screw is broken, or the tang is broken, to have that gap. According to the Chronology section of this board, the last recorded two piece tang is on a Specialty grade shipped July 8, 1915. My theory on the reason for the two piece top tang is that the same forging was used for both the hammer and hammerless Fulton guns, and the long tang was not needed for the hammer gun. The were no hammer guns built on the FW frame, so there was no need for a shorter tang forging.