What Would Be the Difference Between a Factory A/T and Manual Trans. Carb?

fast idle speed for an AT is going to be ~50-75 RPM higher.
Vacuum kick orifice size is different between carbs, whatever that does on an AFB.
Get an Carter rebuild kit that covers multiple carbs and there will be all kinds of specs for float height, choke pull off gap, etc. I would think maybe an AT would be a tad richer too for the convertor load?