I have some thoughts to your question. 1st mom and pop store selling gas more than likely could of bought a second hand pump other than factory new may not have change numbers,and not went to wet hose as quick as large chain stations. Large chain stations had attendants you didn't pump your gas. They also had pump service guys that came around and serviced pumps and up dated pumps. Either way is correct because drys was converted. If your pump has a gatevalve and you believe it to be correct for your pump then it was a dry system. I have a fry 5 gallon with external pump it came from factory dry. Wouldn't change a thing ,I get a kid out of explaining how it worked,and also explain kids walk to school and back.LOL!