It's a Kommiefornia thing. The crooks running the state of CA first declared any centerfire rifle having a pistol grip and a detachable magazine an "Assault Weapon", then set a deadline for build date (December 2016) and another one for AW registration date (June 2018). Past the registration deadline, your rifle either needed to be "featureless" (i.e. adding a dumb looking shark fin to the grip to prevent clutching the grip) or converted to "fixed magazine" (you need to pop the action open in order to be able to eject the mag) or you need to get rid of the rifle altogether.
With the delay in production at HMG, apparently some Kommiefornia buyers convinced HMG to send them unfinished but serialized receivers so they could DROS the receivers before the build date deadline, then send the registered receiver back to HMG and have it completed into a rifle before the AW registration deadline. This did not work out as the registration deadline passed without HMG delivering. As the AW registration required submitting pictures of the entire rifle, but no completed rifle existed, the owners now have to write off the idea of having a HMG StG44 in AW configuration. Instead, they have to receive the rifle from HMG in either featureless or fixed magazine configuration. The auction doesn't state this.
Good info re my question about that receiver. Sad for the CA guys.
CA, a good place to be F R O M !