The way the questions on the AMCAS app are worded, you get to check a box for ethnic status
(Not Spanish/Hispanic/Latino/Latina or Spanish/Hispanic/Latino/Latina with options for Cuban, Puerto Rican, or other ethnic), and another box for racial information (black, Native American or Alaska Native, Asian, Hawaiian or Pacific Islander or other. You then get to state what your primary/other language(s) is/are, and whether or not you consider yourself disadvantaged. So, Katie, it's not just a matter of whether one qualifies to "check the box." Which box would that be? How they get out of all this a person's URM status is beyond me. But at least it's not just checking one box -- they seem to be eliciting information that gives a good picture of where one is in the melting pot.
I would think if you're black, you're a URM. Black does not assimilate (i.e. disappear) very well into the melting pot.
Best of luck, Hi and warpath, with your applications! 😀