Not sure if this is the right forum (m4) stamped upper

[XDrigger]

Hi all.
Just a question, I have a flat top upper that I'm curious about. It has the cerro Keyhole, stamped T-marks and "M4" stamped above the gas tube hole on the front of the receiver?
Just wondering if you guys know who might make this upper?
Thanks

[XDrigger]

I did see that Colt has this "M4" mark but it seems they also have the "C" colt mark. So I don't think it's colt. Also it was purchased from M&A parts if that helps?