I looking at getting this or something similar (carbine conversion unit by MechTec) and was wondering how this would be purchased? It obviously adds a stock to the pistol, so it would fall under NFA, presumably in the AOW classification since it's an adaptation based on an existing pistol. Howerver, it could also be considered a SBR. However, since the triggering system and "body" is existing pistol (G27 in my case), I'm assuming AOW classification. Are my assumptions incorrect? Would it be taxed at $5 or $200? Thanks in advance for any/all advice!