No such thing. Colt did make some AR15's in electroless nickel.
Is it possible you mean an AR 15 made with an elcectroless nickel finish?
100-1500 USD or so
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
No such sn in the AR-15 series
it was modified................
On the receiver
AR-15