Air screw "o" rings

I've rebuilt my VM24 carbs twice in 28 years using generic kits. My air screws do not have "o" rings on them (no where to put them), is this normal? Should I have rings? Makes me wonder if air is being sucked through.

Hey John,

I think that the rings do the same as the springs on some adjustment screws. Just hold the adjustment against vibration.

Bill

I just got my kits today for my 24's, and there were 3 different airscrews in the package. All three had o-rings.
They are made by K&L.