Sgt La David Johnson was a wheeled vehicle mechanic.
That was his MOS before he entered SF pipeline. What I can’t figure out about Johnson is whether he was SF qualified. In his official photograph, he’s wearing a red airborne beret, and I don’t see a Ranger or SF tab. However, that could be an old photograph, taken before he gained those qualifications. BTW, after retiring from active duty, I spent some time as a civilian analyst at an Air Force intel production center. One of my co-workers was an ex-Green Beret who spent 10 years as an Abrams tank mechanic before he got bored with that and tried out for special forces. He was the oldest guy in his various courses.
Interestingly, the Navy SF community often referred to SEAL operators under their previous rating before joining the teams. It wasn’t unusual to see a SEAL listed as a Gunner’s Mate First Class, etc. Now, most who are ID’ed are listed as “Special Warfare Operator Second Class,” etc.