Grade 2 means it has some scroll engraving on the receiver and a little bit nicer wood. Very good rifles, good shooters. A bit heavy, but otherwise a go. Price sounds very good. I would check it out very carefully. Things to look for:
* Peened receiver right in front of the op handle means someone has had trouble getting it cleared if it jammed and used a screwdriver as a prybar.
* Split forearm around the retainer screw means someone may have overtightened the screw and got it jammed in the gas block then had to pay a gunsmith to take it out.
* Buggered screws on all the parts means it's been taken apart by a gun monkey.
* Scratched or worn bluing on the receiver or anodizing on the trigger guard means it's been carried a lot. Not a disqualifier, just ugly.
Have it checked out by a gunsmith, but the BARs are pretty hard to screw up. Sounds like a good deal. If it's clean, jump on it.