At one time, Missouri did not assign state highway numbers in the 400 series. That changed in 2000 with the opening of the James River Freeway in Springfield. As a result, highway designations shifted, with the former Missouri 13 along Sunshine Street becoming Missouri 413.
Also notable is the "wide" (rectangular) marker, which is a wide version of the standard Missouri marker, rather than the "pointy" marker that has been used for a couple of signs along Missouri 763 in Columbia). The rectangular markers came into general use for three-digit highways starting in 2000.
Photo courtesy of Dave Backlin (taken May 2000)