City Politician's have no right to that information. All that will come from that is the possibility of Doxing law abiding citizens, because they surely won't use it to go after criminals. F@#$k Them!
I suppose the only thing to make sure is that you have the correct paperwork for the sbr. Otherwise have fun building it. Looks cool as shit... I have two cx-4's both stock. Fun guns to shoot and very accurate.... Triggers suck but hey still plenty fun...
Does this same thing happen with multiple mags? I like to number my mags in case these things happen to give reference to which mags don't want to play nice.