Looks like it was a fashion to modify Mauser's front sight in the old era. Probably because it's an integral part of the barrel and it's fixed, and that inspired some work activity in this gun's "tool stage". The gun has been in "collector stage" for long time. When I initially received it, its internal protective grease had dried out.
I just browsed GMA. Interesting enough, they just sold another Bolo rig yesterday, and it also has a non-standard front sight -
http://www.gregmartinauctions.com/Au...px?LotID=14700