German WWI S98/05 Butcher Bayonet, Mauser Mfg, Filled In Pommel, 1917

Original period manufacture. A most unusual variation of the standard 98/05 Butcher bayonet, manufactured by Waffenfabrik Mauser in 1917. Bright finish blade, factory edge, just minor spotting and clouding to the surface. Crown W 17 on the spine, steel flashguard is in place. Original finish serrated wood grips in sound condition. The pommel has had the lock mechanism expertly removed and the holes for the push button and stock stud have been very neatly filled with machined steel. Even and matching steel patina finish to the guard, pommel and flashguard. Blue steel scabbard in clean condition, no denting or surface corrosion. It is not Mauser marked so the scabbard was swapped out at some point in the past. After the end of WWI a number of original bayonets were modified for Police or civilian use, with notches cut into the tops of the pommels, or filled in as this example. No other markings beyond the Mauser name and spine issue stamps. What am I...?