For history of companies such as Union you can Wikipedia them or use the Google search within OG function which is in the upper right of the page.
Red Line is a brand of Union Oil founded in Santa Paula Ca and that symbol for Union was in 20-30s time frame. Click the link for more:
http://www.oldgas.com/shoptalk/ubb/Forum4/HTML/001418.htmlThat can looks to be in pretty good shape for its age.
I am sure that one of our OG members who happens to live in the city of Santa Paula will chime in once he gets his shorts and sandals on. It takes him a while to get going! And I suspect you might be baiting him.