The special handling fender tags are common to police cars, lots of folks have saved the tags from salvage yards over the years & added them to their cars.
I have never seen an original Hamtramck or LA built car with one of these tags, they noted their special handling cars on broadcast sheets instead.
The 'special handling' had to do with the vehicle build, it had nothing to do with being able to 'handle' corners at high speed.