To back up BillBond with his comment that most people on the EE board here are honest, I just traded for a Colt SOCOM barrel w/ a 10/08 date stamp that the seller said had 300rds fired. I think he "lied" as I have found no evidence whatsoever that the barrel had been used at all. I got a barrel with no finish wear evidence on either the barrel nut, receiver extension, or muzzle threads from mounting. There was no firing evidence, no evidence of cleaning. There is evidence of oil/preservative from the manufacturing process. I got a new barrel that had been advertised as used.
Ive found it easier, and common with others as well, to sell "underrated" so as not to have to deal with a buyers false expectations after a sale.