O/T Mileage wrong on bill-o-sale??

[svx_commuter]

I am looking at an Astro van with 83k miles on it. I tell the guy I will buy it and he says one problem. The bill of sale has 96160 miles on it. He says it was wrong when they issued the bill of sale but he did not notice until years later. He tried to contact the old owner but was not successful in getting a leter to change it. Does this sound okay or is the guy BSing me? It has one those digital odometers and the car looks like it has 20k miles on it.

Thoughts?