The grain dealer license shall be posted in a conspicuous place in the place of business. In the case of a licensee operating a truck or tractor-trailer unit, the licensee is required to have a decal that the license is in effect and that a bond has been filed, such decal to be carried in each truck or tractor-trailer unit used in connection with the purchase of grain from producers. (1973, c. 665, s. 6.)