In response to Sgt.'s Frank Huff & Steve Krupa posts about a DI Sgt. Thornton at MCRD San Diego. There apparently was more that one DI named Thornton, as I was there June 23, 1973, Plt. 1070 and my Senior DI, was a SSgt. Johnny Thornton. While it's possible he was a Sgt. in 71, I don't know that, but here's a pic of him from my boot camp annual.
Fred Lowery
Sgt. USMC 1973-1976
Engineers 1341/1345
No matter where you go, there you are! "Buckaroo Banzai"