Your pump looks like a Southwest 40 model to me. Is that right?
I follow Conoco and its use of gas pumps, and Conoco only used a limited number of Southwest pumps, almost exclusively in Texas....where Southwest is based. I did some limited digging into the Southwest gas pump company and what I found seemed to suggest they were a small local gas pump company. Based on what I read, I am a bit surprised that they would have supplied a retailer in Colorado. Can any others share any more info on Southwest?
...Southwest supplied MANY pumps for Gulf Oil, especially in the 1960s, and they were used all over the country in Gulf's marketing territory...