Some time ago we had a thread on dating one's Rand McNally and H.M. Gousha printed maps. I looked around my "office" and found my list, so I could date the Cities Service map I won from Mick. (Oh by the way Kevin, thank you for not bidding against me! The date on the map is 1932)
Here is a site that gives the codes for these two map printers;
http://www.roadmaps.org/date.htmlThey include the following years 1919 through 2008 for Rand and 1927 through 1996 for Gousha.
I want to thank "The Road Map Collectors Association" for having this information, available.