Missouri Hwy Cast Iron Road Sign

The attached article explains the history involved but in case it is difficult to read (due to size of image) - it was found in the rafters of my turn of the century home when installing phone lines. This highway is now Hwy 14 in Christian County, MO. The local state college (now MSU) could not find info about Hwy 40 and referred me to MoDot. They were able to look up the existence and time period of the old highway and it's history. The map (attached pic) was done to show the highway system back when this sign was in use (range of just before the 1920's and including the 1920's). MoDot (MO Dept of Transportation)told me this sign is the only one left in existence. Also attached are 2 pictures (front and back) of the sign.