I'm not 100% sure, but according to this thread;
http://206.82.221.135/showthread.php?p=12483303 I'm thinking
NO.
"...Brazilians nor Argentinians have been identified as underrepresented in the medical profession by AMCAS."
"Before June 26, 2003, the AAMC used the term "underrepresented minority (URM)," which consisted of Blacks, Mexican-Americans, Native Americans (that is, American Indians, Alaska Natives, and Native Hawaiians), and mainland Puerto Ricans. The AAMC remains committed to ensuring access to medical education and medicine-related careers for individuals from these four historically underrepresented racial/ethnic groups."