I did not receive a reply from the DMV Emissions Co-ordinator, but the following is posted on the Exempt screen for the CT Emissions Program, note the 4th item, looks like it really did happen !!
Exempt Vehicles
There are some exemptions to the program, particularly newer models, many older vehicles, motorcycles and other specialized vehicles:
* New vehicles that are four or less model years old (as of 1/1/07 model years, 2005, 2006, 2007 and 2008).
* A motor vehicle twenty five-years old or older, (as of 1/1/07, model years 1983 and older).
* Vehicles with a gross vehicle weight rating of more than 10,000 pounds, such as certain heavy-duty trucks or recreational vehicles
* Composite Vehicles ( Effective July 1, 2007)
* Electric-powered vehicles
* Bicycles with motors attached
* Motorcycles
* Certain vehicles registered but not designed primarily for highway use
* Farm vehicles
* Class-1 School Buses
* Vehicles with Dealer, Repairer, or Transporter Plates while official tests are obtained
http://www.ctemissions.com/exempt.html
I was previously advised, forgot the source, the model year exemption had been changed to 20 years, but the above indicates 25 years ?