m4220,

that dedication on your gun reads to me:
Wilhelm Haase s/l. Bruder Gustav
Wilhelm Haase s(einem) l(ieben) Bruder Gustav
Wilhelm Haase to his beloved brother Gustav

My reference was to the Prussian Emperor (or Kaiser) Wilhelm II
http://www.germannotes.com/hist_kaiser_wilhelm.shtml
He had a crippled left arm, had to shoot practically one-handed. It seems he preferred guns with a very steep pistol grip, hence the "Kaisergriff".
This is very popular today, especially on Ferlach guns, although it's ugly and not at all useful if you have two good arms and hands.
On an old rifle this form is rare.

Really looking forward to the article!

Fuhrmann