scamp VS dart

A Swinger and a Scamp are effectively the same car! Well save for the hood, fenders grille, front bumper and 3 emblems.

So tell them it's a Dart with Plymouth fenders!

Or, get a supplemental policy to make up the difference.

I very much doubt the government can require anything other than a minimum level of coverage. Somebody is feeding you a line of BS. Contact an attorney if need be for advice. If the Sask Provincial govt runs the insurance, there should be no shortage of attorneys specializing in insurance matters.