ORIGINAL: Snipin_Willy
I pretty sure all the idle screw does is limit how much the carb is allowed to close. Personally, I'd wait, I wouldn't want dirt and grit getting in the hole where the screw goes. Hope you ordered the spring with the screw also.
Exactly, it technically wouldn't hurt anything, as long as your car still runs. Although if dirt gets in there, it could eventually find its way to the engine. Not to mention getting dirty threads for your carb needle.