Yes, that's all it is. A shorthened G3 housing, which is no problem. All the full size semi auto housings are the same spec in all regards except the 308 housing has the longer tang for the double push pins. Many MP5 semi auto housings are nothing more than a G3 with the tang properly shortened. However I am sure a factory German MP5 semi auto housing is not cut down, and manufactured with the shorter tang from the get go.