Your pump appears to be an American #1. It is not the first pump made by this company because when they started making pump they first use an "A", then a "B", etc. Your pump was the first one to use a number rather than a letter. Originally the pump was painted all red, green was used for kerosene.
Your pump is shown on page 40 of my new book called the Gas Pump Bible. It is available at: www.gaspumpbible.com
I show some literature on your pump on this page: http://petrolianacollectibles.com/gas%20pump%20literature.htm
Click on American, then click on "1."
American was a large company that started in business in Dayton, Ohio. In 1914 the company's offices were moved to Cincinnati, Ohio, but they continued to make the pumps in Dayton.