I've got the same one. They ain't going to get any cheaper.
It has a SCUBA fill fitting on it. Ask if the pressure switch is set for 300 bar. If not, that may be a bargaining chip. Take a tank over there and have them fill it. It should start on first or second pull. Honda motor is bullet proof. It's overkill to fill a gun. You will overfill it in seconds. Trust me; I know....
See what kind of oil they are using. Don't cheap out. Coltri Oil is a must. A rebuild can cost just south of a grand.
If they'd take <$2500 it would be a good deal.