I'd disagree. It's at least a 5hp, possibly 7.5hp compressor complete with a starter and single phase motor. If it runs ok and I could pick it up for $500, I'd call it a bargain considering you could barely get a bare 5hp HF pump for much less. The tank was made in 1984, so it's not the newest thing around, but plenty of people are using older ones. A decent single phase motor could get most of your money back if it was a dud. The pump is an ABAC, whic is an Atlas Copco brand. BelAir, Chicago Pneumatic, DeVilbiss and Quincy have all used these pumps for their cheaper lines. If it croaks, put on something else.
Caveat, I wouldn't use it for any heavy duty work like sandblasting.