The hardware is Wiedmann style but the ISA's a SHuCo. Stewy
This one is a semi-hollow ShuCo Design as Stewy states. There are multiple firms in the Oberstein area that utilized this obverse design and who actually manufactured it is not known. The lily pad hinge hardware can be found on other makers with Wiedmann being the most familiar. Most likely this hardware system was made by a vendor and sold to different makers. That said, this is the only variant in the ShuCo family of Infanterie Sturmabzeichen's to use the lily pad hinge.
I consider these examples late war produced with the change from solid zinc to the semi-hollow design and the low quality finish that did not hold up very well.
These are difficult to track down and are one of my favorite ShuCo Design examples...Congrats on finding a nice one...
Best regards, fischer
Thanks for the info guys! Fischer I appreciate the additional input, very helpful!