Colt carbine variants with flat top and pencil barrel ?

[1986s4]

That’s the only Colt factory carbine with that combo of flat top/pencil barrel features that I’m aware of too.

The Diemaco C8A2 would have been quite close however. I think these were produced before Colt bought Diemaco so they aren’t actually Colt guns though.
But they have flat top uppers (possibly not technically M1913, Diemaco for a time was using a rail on their uppers that was similar but not dimensionally identical to the M1913) and 14.5” lightweight barrels (that are .750 at the FSB though, vs .625)

Thank you, that is what I meant, military carbines. I should have been more specific.