It's only fair to test the cars according to the emissions requirements of when they were sold. This law is stupid since the problem will pretty much take care of itself. In a few years a large number of the old cars will be scrapped due to wear, and the few remaining will be owned by collectors who drive them occasionally.
If I was a collector I'd be mad, too. Imagine taking a cherry car that's 100% original down to the nuts and bolts, and fitting it with a bunch of junk that was never designed for it.