I have a semi-auto MP5K-PDW (clone) that I SBR'd. Currently it has the folding Chaote stock on it and vertical foregrip. If I wanted to replace the folding with just the standard MP5K end cap, does the weapon go from being an SBR to an AOW in which case I will be in trouble? Or, does it matter since the weapon is still a SBR without a stock?