What you were told on WAF is correct. You can compare it with my example posted here.
Infanterie Sturmabzeichen in Silber,Unmarked Ernst Muller
Searching for anything relating to, Anton Boos, 934 Stamm. Kp. Pz. Erz. Abt. 7, 3 Kompanie, Panzer-Regiment 2, 16th Panzer-Division (My father)
A nice silver Muller ISA. Stewy
very nice item sand as the guys say its a Muller.