For what it's worth, if someone wanted to check it out, first see which transmission is in it and give the exhaust a good sniff. If you notice white smoke and a slightly burned power steering fluid type smell, you might be in luck.
Since it's "heavy duty", it'll probably have a 400 trans. The 400's have a vacuum modulator, to regulate pump pressure based on how hard the engine is working. It's just a rubber diaphragm in a metal housing. If that diaphragm breaks, the engine vacuum will suck the fluid right out of the pan, leaving the transmission useless and the top end of the engine well lubricated. You wouldn't be the first person to score a heck of a deal for the price of a modulator ($50-ish?).
If it's the 700R4, it'll be the early "small shaft" style. Let them keep it unless you need the batteries or tires or whatever.
And yeah, CL is full of scammers, but they're usually trying to sell 2007 Accords for $600 to see who bites...