The two styles of city-limit sign used in Missouri appear just hundreds of feet of each other at the Kansas City-North Kansas City line. The sign on the left (or top if you're viewing this in a narrow browser window) is a freeway-style sign, used on northbound Missouri 9. The sign on the right (bottom in narrow browser windows) is the standard style, used on almost all non-freeway routes, in this case, northbound Missouri 283. These signs are just north of the intersection of Missouri 9 and 283. Missouri 9 goes on to become a freeway for a short distance, connecting with US 169. Missouri 283 is the designation for the North Oak Trafficway, but the trafficway is an ordinary city arterial street.
You'll note that the speed limit on both routes is the same, and that only the non-freeway-style sign includes a population figure.
These photos were taken in September 2008.