All the documentation that I can find says he was a “legitimate bona fide member” of Seal Team One. After already having been a long-term member of UDT Team 12. BTW – SEALS have a special, off the record, unofficial team that chases down BOGUS SEALS! If you’re going to say ‘out loud’ that you were a NAVY SEAL, beware if you were not – THEY WILL FIND YOU!
“There it is: Jesse was in SEAL Team One.” He speaks of his pride as a SEAL: “We’re a proud organization. If anyone tries to pretend they’re a SEAL, God help them. You have to earn the right to be a SEAL warrior.” (p. 81)
But Jesse confuses things by making a single reference, among all the SEAL prattle, to his service in UDT 12: “[After BUD/S] we were sent to our teams. I was part of Underwater Demolition Team 12.” (p. 71)
That’s it. Nothing more about UDT. Only SEALs.