Well, I got it - and for $50. Cabinet is in decent shape, shows some wear but isn't torn up or beaten. I took a bass, instrument cable and amp, but like a dummy I forgot to take a cable from amp to speaker, so I couldn't test drive it before getting it.
Oh, well - I only have $50 at risk, and they did say they had tested it and it worked. The place is R2 Electronics Recycling in Denver - most of what they have is computer-related, but this showed up. I'm guessing they just plugged in a stereo and played music through it, which is quite different from pushing a bass guitar...so I'm not sure the speaker is good.
But if it works, I got a great buy - if it doesn't, the only thing that could be wrong with it is the speaker, and that's replaceable - it would just result in it not being such a great buy.