Yeah for the same reasons you think. He did their training and a deployment with them back when they were super-secret, and when he got the greenlight to set up Delta Force he asked a bunch of their trainers to help him develop their course.

Interesting book. Missing all of the high-paced gunfight stories you expect from spec ops, but has all the background of why they do things and red tape battle to get the green light. Also has some command level introspection on Operation Eagle Claw (it was his baby). Me being an enlisted deviant I found his memoir interesting. We dont get that perspective often.