First, congratulations! This is a good problem to have, and one that many on this board would be envious of. Second, no - each nomination is to a specific school. Understand that the nomination rules to USMMA are different and that any member of congress in your state can nominate your son. It would behoove your son to begin reaching out to literally any MOC that you can reach to see if their deadline or application has passed, and whether they would be open to nominating him. I received a NOM to USMMA in the April time frame (long ago), so there are options.