Hey mjgcarpenter, I have a Class III 12 gauge that could possibly be what your brother is talking about. It is a Mossberg model 500 that was converted by S.W.D. which was some how connected with Cobray. It has a 12 & 3/4 inch barrel and on the left side of the receiver, "THE ROGUE" is cut or laser etched into it. It is classified as AOW and had a $5.00 transfer. Ask your brother if it was a standard type configured shotgun or something unusual looking. Maybe this will help.
Cobray made a Striker 12 that was a drum fed 12 ga. that was in appearance just like the "street sweeper". Both were banned because the liberals didn't like thier names or their looks. I don't know what restrictions are on them now, but I remember the street sweeper ads in the SGN used to boast "12 shots in less than 3 seconds".