WTB M3 piece that rear armor bolts to along the bottom

[col.halftrack]

 I'll call it a bulkhead? It is at the very rear of the M3/M16 and is what everything bolts too. Taillamp corners, bottom edge of the rear vertical armor on either side of the door, and rear bumpers.
 Have lots of halftrack parts too trade or will pay cash.
 Thanks