I've been wondering about this, too. I've always been able to just kinda jiggle them out or even simply slide them out, very easily. I JB'd one of them... I think the one the ICV is on. I think it's time to JB the other two, especially since even after the engine swap, I have the troublesome idle, and the dead spot when first giving it throttle. Maybe these are to blame. I think we replaced every vacuum hose, but these little metal dudes that slide into the throttle-body I am still worried about.
Also, my Paps was humoring the possibility of the butterfly rod wearing out where it contacts the housing, possibly allowing air to pass. It stands to reason that this is a possibility, but would like more input.