Once upon a time,
In 1969 an almost identical plain and basic, replacement wheel cover to fit a 1969 Plymouth sedan sold for around $20.00 retail.
They both were packaged in brown paper bags which were imprinted with the words Mopar Replacement Parts.
The only difference other than a painted design and the part number was the 1969 part included a small piece of paper in the package that stated the enclosed part met all the New US Department of Transportation standards and included the code number to which it conformed.
I remember that well at it was a 100% price increase for absolutely nothing.
But then, the 1969 wheel cover was Certified as being Safe by the Government.
The reason was that if you were hit or run over by a US made car, the government didn't want you to suffer an additional harm caused by protrusions on a Flipper Wheel Cover.
Thus, the horrendous safety problem was resolved. You see, that was before we had Issue to address.
http://www.chooseyouritem.com/classics/photos/106000/106001.1968.Plymouth.Valiant.jpg