I guess what threw me here is the carb has for the primary, a large idle screw and for the secondary a thin idle screw. Both had light green gaskets (perhaps they are o-rings) in there now. There is no way one of those little black o-rings would have fit over the thick, primary idle screw. Also, when I took the carb apart, there were a few of these old black o-rings that came off and I didn't note where they had come from. That's why I thought they weren't associated with the idle screws.
no matter, the carb is back together now and on the car. I started her up just now and she is running much better. I still need to adjust the choke, and the mixture.... still more to learn