The picture above shows the end lettering on a tank from 1913. The picture below shows the end lettering on a tank from 1916

Note the different end piece found on the 1930 tank when compared to the 1925 tank. 

Early tanks were marked with a Capy of 100,000 gallons until someone realized that was way too much and changed it to a more realistic 10,000 Gals. Both tanks above are from 1916.