It's like here in Massachusetts, we are still under the 94 AWB, (REPUBLICAN MITT ROMNEY) made sure it never sunsetted here, (remember that when you go to the polls) - he's a traitor to the 2nd Amendment...
Anyway, ask any cop - from local PD to State Trooper, if he really cares if your 30rd mag is preban or not...The resounding answer is "no"... One LEO I know put it best: "If I pulled you over and noticed you had brand new Beta Mags and new P-Mags, (both illegal here) and you were cool - I'd be cool. If I pulled you over and noticed you had those mags and you were a douche, then all bets are off....
Bottom line: Live your life for Gods sake...Most cops could give two turds about 922r.....