Regarding the original question, I can tell you that when I took the Blue Mule (74 FJ40) in for emissions testing it did not have an air pump and I had plugged the air injection holes and it had an after market exhaust header. All they did was a sniff test and never opened the hood. At that time it was running on 5 cylinders and overall ran like crap, but it still passed the sniff test.
Isn't there still a clause in the law that says if you fail the test, you don't have to spend more than X dollars trying to get it fixed? The amount you spend is related to the age of the vehicle I think. I would think it would be easy to have receipts that meet the dollar value just by documenting say a rebuilt carb, tune-up and the labor to do those things.
Also, just 2 weeks ago we got collector plates for the 57 Chevy and no emissions test was required. Maybe because it is so old? Good thing too, because it currently smokes like a steam engine
These laws defy logic.