Hi @jchandler Welcome to the Canvas Community. Unfortunately, it is not. Roll Call attendance is pretty non-configurable, frankly. What I recommend to my own faculty is to create separate assignments for class participation. While you'll have separate items appearing for roll call and for participation, it's really the only way to solve this. You will want to consider putting these into its own assignment group and then, perhaps, weighting that group according to the way you choose to grade those items. (This is one way around dealing with the fact the attendance always wants to be 100 points. Be sure to read through this lesson, too: How do I edit the Roll Call Attendance assignment? ). The downside is that you may go a bit crazy coming up with daily class participation assignments. I normally advise my own faculty to create a monthly participation assignment....or unit/chapter, based, depending on how your course is organized.
Finally, to bring you up to speed a bit on the pitfalls of roll call attendance, take a look at this Feature Idea and the (many) comments below: https://community.canvaslms.com/ideas/1090-attendance-overhaul .
I hope this helps a bit, Jennifer!