If the student is eligible in local context (UC-recalculated GPA exceeds the top 9% UC-recalculated GPA for a recent previous class at the high school), then UCM may offer admission if the student gets shut out of all other UC applications.
But if UCM could be anything other than the last choice UC, better to include it in the UC application.
Have not heard of UCR doing eligibility in local context admissions recently.