I know two.
I earned a Black Belt under one, Vietnam era. Most of his buddies died violently and he was still suffering from nightmares 20 years later (when I knew him) all info from his wife. He NEVER talked about it. I think Instructing Martial Arts was his salvation and penance. Wise old man now.
I know one other four years younger than myself (51) long retired. Burned out knees. He was in around 1980. Rumored to have been in the Grenada mess. He was in a demo type jump team after that, refused to talk about anything and/or be photographed when he was still in, or after for that matter. Started a small business with a nice woman. I knew him as a crazy MF'r during as a young man. He was born with a Seal body, small and lean, NO fat.
Not gonna find out much from real Seals.
Fortunately never met the bragging fakes.
Just my .02