Urban Legend or fact? - Bf 109 with Schräge Musik

[PhilippeDM]

Dear Folks,

Walking through Karl Ries "Dora ¨Kurfürst und Rote 13" Vol. 1, I came across next caption (p.103 - mid picture) (free translation): All the 30 victories of Major Friedrich Müller were made by night while he was part of the "Wilde Sauen" (JG 300 and NJG 11). This picture shows his rudder tally on a Bf 109 G-14 (?)* at the end of the war. Major Müller ordered a MG 151 to be built after the cockpit of his 109 G-14 as "slant weapon" (Schräge bewaffnung)!*

My question is if there were Bf 109 with this "Schräge bewaffnung" and if yes if there exist pictures of it?

(* question mark and bold text are my additions)