Sorry little confused. Are you at an NROTC unit? and they sent people supply?
I graduated from Notre Dame ROTC in 2005. We had one guy go supply. In 2006, they sent another two. Don't know exactly what they had to do, but I know they were not NPQ. Again, I think you just need to have a class advisor who's willing to do some legwork. But like others have said, there's definitely no guarantee.