Can you post a picture? Only thing I can think of is that someone chopped the barrel down on a hunter model and didn't bother to rethread the barrel, or KT made some state compliant models that didn't have threading to begin with.
I'd be willing to bet the previous owner chopped the barrel down.
Is the barrel crowned or just flat?
That might be a good indication.
You might want to measure that barrel to make sure it is at least, 16", and not an "unauthorized" sbr.
The standard RFB carbine is 18".
They made a canadian export compliant model. Couldnt be threaded for a muzzle device and cannot be chambered in a nato/military caliber to legally export... Read the ID label, If it says it is chambered for 308 vis 7.62 then it is a canadian model. Someone there screwed up and they released a few of them that were sold in the US. They made an effort to recover/exchange them once they realized what happened, but I suppose not everyone turned theirs back in because of the unique factor...