nope, it was esso....exxon still operates as esso in certain parts of the world such as barbados.
ENCO and ESSO actually were the same. Just used in different parts of the country. It goes back to the early part of the 20th century and the break up of Standard Oil. Really gets complicated, Humble Oil is in the picture too.
Just wish I had kept that silly 'tail'...LOL.
Bill