Help buying ar15

[bass pro]

I'm new here.This seems like a great place for me to start.Iwant to buy an ar15.Have found one thats a colt le6920.I'm told its brand new,what can I tell from the serial number.Its from a private party,I went to Colts web sit,they have a serial number look up but that comes back no information??? Could it be currant production when the manual it comes with says 2009???What should I look for?? Thanks