Wow! That is certainly a non-standard location for a unit marking and I suspect it is also a non-standard (i.e. not in accordance with marking directives) marking. I am going to take a stab at it. I think it might be a honorary unit designation and I think it might be:
Landwehr Infanterie Regiment Kaiser (König?) Wilhelm II Nr. 2, 1st Maschinen Gewehr Kompagnie, Waffen Nr. 45.
Now let's see what someone that knows what they are talking about says it is!
