If I'm not mistaken, you can shoot a rifle/pistol cal. carbine/rimfire rifle on either day. They're making separate squads for long guns and they'll shoot together but I don't think it's limited to Sunday. At least I hope not because I'm showing up Saturday morning with my carbine. This is from the email notice I got:

We will have BOTH Saturday andSunday Schedules!
You can shoot either day orboth days in different divisions.
We are also going to allowCarbines, Pistol Caliber Carbines and 22LR carbines.
We will squad the Carbine folksseparately so that we can easily keep the pistol scores separate for when wesubmit them to USPSA.
To do that we have 2 DIFFFERENTregistration links, one for Pistol and one for Carbine.