I do see a phone number at the individual listings on that site, but searching the site for your serial number comes up with nothing. A google search on H54J001591 comes up blank as well (not even Stovebolt, which is kinda weird)
Like I said, likely a broker site, as just selecting "Chevrolet" comes up with listings in lots of locations. The police officer you talked with should be savvy enough to realize that not everything you see on the web is true.
