German Cavalry Saber with Scabbard, circa 1864-1891

Unknown model German manufacture cavalry saber, three-branch guard (two side branches with a D-guard), circa 1864-1891. Could have been Turkish issue as what appears to be some Turkish markings are visible on the blade, hilt, and scabbard.
Blade is stamped on back-edge with a crown over K (for German King Karl). Obverse ricasso is stamped with "Turkish" marks as well as what I believe a spurious US stamp over WRR. Reverse is stamped with a crown over D.
Overall lenngth in scabbard is ~41-1/2"; overall length out of scabbard is ~40".
Curved blade is ~34-1/2" in length; brass hilt with leather grip bound by twisted brass wire.
Good to Very good condition overall. Unmarked/unknown maker.
Scabbard is sheet-rolled-steel with most of its "field brown" oxide finish remaining overall. Several very small dings.