Tom, air cleaners might restrict flow a bit at high rpm, but really not at idle. And since the amount of fuel drawn from the jets is proportional to the velocity of air passing across the jets (greatly oversimplifying!), restriction wouldn't necessarily change the air/fuel ration.

But anyway, if the car runs well and this is a temporary setup, I'd say don't go nuts arguing with it. You can tell if the seat for the idle mix screw is shot -- you should be able to kill the motor by turning it all the way in, regardless of jetting (only at idle).