As the mother of a child who is often excluded from birthday parties let me put in my 2 cents. My son has Aspergers so making friends is difficult. He is in 2nd grade and to date has been invited to 2 parties this year and is planning his own party in a few weeks. I cannot tell you how much time I have spent worrying that no one will show up to his party!
I would talk to your son about why he doesn't like these 2 boys. If there are legitimate reasons, they are bullies, they push him on the playground, etc. then I would consider not inviting them. If it's just a case where he says, they don't play with us, or they're kind of weird, or something like that I would talk to your son about everyone being different and having their own way of doing things and that perhaps he should give them another chance.
Good luck,
K.