Some of the old Pioneer and Kenwoods were real beauties, and go for way more than $250. Some of them had art deco looking faces, with tube tuning indicators and independent gauges for AM and FM. Beautiful pieces. I would love to own one myself. That being said, there were some Pioneer pieces that I wouldn't pay that kind of money for at all. If the piece looks so-so, it's probably nothing special. Take a look at the transformers in it, if they're really nice and beefy, that's a good sign. If they're "open frame" without end bells, or smallish, or the thing doesn't weigh a lot, I'd pass. Like jcmjrt says, there is a lot of decent "known quantity" vintage gear at the $250 price point. All of it needs resoration, even if it currently "works". That should also factor in to your decision, how much restoration/modification this piece has.
Good luck, tubes are fun!