First of all, where on the pump was it listed as a pre-visible. This is like looking a tomb stone that states the person died on the year 2 b.c. There are is no such pumps as a "pre-visible." In a resent gas pump book there was a picture of an Erie pump. Below the picture it stated the pump was a 1908 Erie pre-visible. Well, Erie didn't go into business until 1922, and the pump shown was introduced in 1935. My point is that the term "pre-visible" is something we invented, it wasn't used by the pump companies in 1920 and many pumps made years later are grouped in this catagory, just because they look old.
For instance your 480 came out in 1920, after Guraranteed (Fry) and Fleckenstein had already marketed true visible pumps. If you really want to get technical about the term "visible," Tokheim's first pump had a glass cylinder with measurments on it, so actually Tokheim came out with the first visible in 1891 so all pumps are post-visible.
In my new Gas Pump Identification book I refuse to use the term "pre-visible" because again people will call a pump a pre-visble just because it looks old.
If you have a copy of my book, look on page 292, there is a Tokheim 483-G. If one of these were found all rusted, by someone who didn't know much about pumps, they might call this a "pre-visible" but it came out in 1948.
Your 480 was introduced in 1920 and is basically a hand-operated pump with a meter.
Jack
Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at
www.gaspumpbible.comAir Meter ID book also available