The B250s are the 3/4 ton vans.
That odometer is just one part of the story.
In all honesty an engine could have serious problems at the 30,000 mile mark.
Years ago, I had an '84 BMW 318 that had the odometer stop at 380,000 miles.
According to the service records that came with the car when I bought it, that had been several years before, so we estimated that it probably had around 425,000 to 450,000 miles on it.
It ran just fine and was reliable until we sold it out of our circle.
Granted, this is a Dodge, so it's probably about spent (just kidding), but you just never know until you get a good eye (and ear) on it.
Besides, it looks like he's got it priced about double what they're going for around here.