Assault weapon is legally defined. The "usual enthusiast's" definition is irrelevant. Factory SKS, Saiga, and many other semi-autos do not fit.
Damages are always tricky in this sort of case, but given the use of google in employment screening and negative connotation of "Assault Weapon" I think some reasonable claims could be made. Effect on corresponding criminal case could also be argued. Have you seen the damages for those incorrectly incarcerated?