Mystery Postcard, ALA Detroit Conference 1970

What does a postcard showing two young women smiling over a car or truck engine have to do with the American Library Association's Conference in Detroit in 1970? On first glance nothing, but turn the card over and there is a blurb which ties the postcard to the conference and also to the Free Library of Philadelphia. My guess is that this postcard was part of some kind of a recruitment packet or handout for the Free Library. Back then there were lots of library jobs and large public libraries routinely recruited new employees at ALA conferences. The 1970 Detroit conference was the second ALA conference that I attended and the first as an employed librarian. If my guess about the postcard is correct, the women in the postcard were probably employees of the Free Library of Philadelphia. I wonder how their library careers turned out.