Need help identifying upper

[heijutsu]

I have this upper and the only identifying mark is in the attached image. Looks to me like a keyhole. Any help is greatly appreciated.

[Iraqgunz]

That basically indicates a Cerro Forge upper.

https://www.m4carbine.net/showthread.php?t=5357


I have this upper and the only identifying mark is in the attached image. Looks to me like a keyhole. Any help is greatly appreciated.

[5pins]

Is that a left handed upper or is the pic transposed?

[dail621]

Is the numbering on the rail odd or even?