This 58 W500 was for sale a while back, I don't know anything else about it. If you have any pictures or information to share I would be grateful

Found the original AD!

http://www.new-web.com/firetruck/

1957 Dodge 318 4X4 Fire Truck: 300 Gallon Water Tank 265 GPM Pump PTO Pump for Ponds 3 Hose Reels and Hoses Gauges, Sirens, Lights Back Seat Full Tool Boxes 6 Mud & Snow Tires 24,000 + Miles Clean and Nice $9990 For More Info Call 707-995-2515 and tell them you saw it on the Internet

My feelings:

Of course this is a 58 not a 57, but hey at least you now know more about the truck!