Gravano did his service out of state. He never left the country.
Montiglio, I'm fairly certain, went to Vietnam; but it is highly likely that he exaggerated his tales of valour - as a lot of his stories cannot be corroborated.
Gravano's Service was actually quite honorable, nor to his credit, does he embellish his service.
Montiglio was a shitbag and more than likely fizzled out of training or had a short Active Duty career.
Sal Vitale was kicked out of training (OSUT).
Mickey Featherstone was another lying shitbag.