This is a SAR-3 which is a factory Cugir 223. It's had a 74 style muzzle installed and has been refinished. The muzzle brake does not seem to be a standard 74 type indexed with a pin on the fsb. It's unclear whether it's installed with an adapter, or maybe some pressed or pinned unit. It didn't want to unscrew with i tried it, but I didn't crank on it too hard.
For more pictures or if you have any questions, please text or email me, as I don't check this often.
303-731-6009