Here's a prototype 1982 CHP Mustang with the same wheel covers as the 85/86 NSP car pictured above -
This Mustang does not appear to be the same CHP prototype car owned by MikeS. A few differences (besides the black roof) are: no 5.0L badge on fender; chrome rocker moldings; and no hood scoop. But I remember those wheel covers on non-V8 cars back in the 80s.