Bayonet holder, flash hider.
100-1500 USD depending on specifics
You will have to call COLT
$1384.99
AR-15 is a trademark owned by Colt - thus, no other manufacturer may market their rifles as AR-15 unless they are specifically licenced from Colt to do such. LAR-15 is simply Rock River's alternative name to "AR-15" in order to avoid infringing on Colt's trademark.
You will have to call Colt with the sn to find out.
You will have to call Colt to find out.
Colt data at Proofhouse.com
The LBDXXXXX serial number was designated for the Colt AR-15A3 Tactical Carbine (AR6721) post ban. Pre-ban version had the BDXXXXXX serial numbers. (there less than 200 of those released). Colt started using the LBD serial numbers late 1995/ early 1996. The "L" was soley for the Law Enforcement Restricted models that had the "Restricted, Military/Government Law Enforcement/Export Use Only" roll marks on the magazine well.
No such sn in the AR-15 series
it was modified................
On the receiver
AR-15