Who made flattop uppers with the T numbers?

I recently purchased a upper from someone off of assaultweb. The upper was advertised as an ASA M4.  

Well, the barrel is M4 profile with a cav comp style muzzle device.  However, the upper itself has T numbers.  I called ASA and they said they have never made an upper with the T numbers.

The bolt carrier that came with the upper does have a C marked on the non ejection port side.  Is this a Colt carrier?

thanks in advance

medcop

edited to add: The barrel does not have any markings on it.

I have a postban Bushmaster Dissipator with T Numbers and a friend of mine has a preban Colt with T Numbers. I have also seen others. I think your going to have a hard time figuring this one out. Wish I could be more help.