Absolutely new Colt M4 flat top upper receiver with RAS T numbered rail. Yes its marked with the letter C and is stamped M4. Yes it has the M4 feed ramp enhancements. This upper came to me new in wrap from a Colt distributor and has never had any parts installed. I am asking $250.00 plus shipping. Pics and references available to a serious buyer. Please contact me via IM or e-mail at CLM4@EV1.NET.