Jim - It looks like the Denver Library is a
repository for the historical documents related to the company. They don't appear to be available on line, but a direct visit to the Library might figure out a way to get access and possibly document some of the history of your truck.
There are a bunch of rules and limitations on what can be copied/photographed from the collection, which would need someone's approval for sure. But if you really want to know, this is the place to start.
