I think the best example of a map series using Rand Mc Nally map codes is the SOHIO Ohio map series.
SOHIO used Rand Mc Nally maps from 1924-1926, 1930-19-1985.
Your device may be up to date if you docked your device frequently or recently purchased it.
Rand Mc Nally & Company, still a major name in map publishing to this day, began as a small print shop opened in Chicago in 1856 by William H. The shop originally printed guidebooks and directories.
In 1858, Rand hired Andrew Mc Nally who was later to become a partner.
The codes are generally publication dates jumbled in a certain, consistent way that are often preceded by the letter C, although this is not always the case.
Maps from the 1930s will often have three-digit codes containing just the month and last two digits of the year, generally in that order; 336 = March 1936, for example. 15 1957 (date  last two digits of year reversed [75 = 1957] month ) 124511 = Nov. Clason maps are notorious for having no date information.
The first map to really distinguish the company was Rand Mc Nally & Co’s New Railroad and County Map of the United States and Canada, published in 1876.
This map formed the basis of numerous further publications, since it could be broken down to show different states or regions.
All updates are completed using the Rand Mc Nally Dock.
The Rand Mc Nally Dock is a software application you download and install on your PC/Mac.
12, 1954 (date  last two digits of year reversed [45 = 1954] month )1744 = 1947 ["74" reversed is "1947"] 218412 = 1948 20353 = 1953 1354 = 1953 C-11558 = 1955 15658 = 1956 C-15857 = 1958 C-1859 = 1958 C-5361 = 1963 After this date they seem to use more standard dating, e.g., 9-67 = 1967. Instead, various elements of the maps changed over time.