Section 137.115 RSMo. The assessor of each county and each city not within a county shall use the trade-in value published in the October issue of the National Automobile Dealers’ Association Official Used Car Guide, or its successor publication, as the recommended guide of information for determining the true value of motor vehicles described in such publication. In the absence of a listing for a particular motor vehicle in such publication, the assessor shall use such information or publications which in the assessor’s judgment will fairly estimate the true value in money of the motor vehicle.