I didn't know that, no, but I should have. I have a GG&G flip sight on the faux gas block. The MBUS front sight would have been cheaper. It is a CMMG dedicated upper, 22 LR, blowback operated. A really fun little gun.
I missed the 22 part initially, which obliviously means you don't have the same concerns with the gas block getting warm. The dedicated 22 uppers are certainly a hoot to shoot, aren't they?