Based on what YOU posted, you were not following the law. You said that you went to the junkyard and then you went to the inspection station. Per Missouri Revised Statutes Section 307.350, here is the law:
2. For the purpose of obtaining an inspection only, it shall be lawful to operate a vehicle over the most direct route between the owner's usual place of residence and an inspection station of such owner's choice, notwithstanding the fact that the vehicle does not have a current state registration license. It shall also be lawful to operate such a vehicle from an inspection station to another place where repairs may be made and to return the vehicle to the inspection station notwithstanding the absence of a current state registration license.
(from http://www.moga.mo.gov/statutes/C300-399/3070000350.HTM)
You were operating in violation of the law (per your original post.) Congratulations on convincing the chief to give you a break.
Oh, and to be clear: You were 100% WRONG.
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