Vintage and value of Old Colt AR15 Carbine....

Friends;
I'm trying to ID an old Colt AR15 upper and need your assistance...It's an A-1 Upper w/forward assist--duck bill suppressor--big locking pin and small pivot pin...It has a thin barrel 16" and appears to be of the Carbine Family..Color is a grey -- not black..Colt ID of C within a square and inverted triangle with VP inside stamped on receiver below A-1 Sight near pivot pin...That's the best I can do for identifying marks..I'd appreciate any direction or suggestions or pin-point recognition any of you folks could offer...Many Thanks -- Appreciate your time and expertise...Bluegoose66

hello ,,i can.t tell you exactly what you have ..but can give ya some dirction,,try over on AR15aromory.com,,there a good bunch of guy with lots of knowledge and will answer questions from newbies and the sites devoted to ar style weapons and variations,,heres a link http://www.ar15armory.com/forums/General-AR15- Discussion-f193.html
bigcurt