Nevermind! The studs are indeed threaded in. Super easy to back them out with a pair of vice grip pliers. I chased the threads with a tap after removing the studs. Then I replaced them with 25mm long low profile socket head cap screws from McMaster. They are still very close to the cowl, so I put a piece of foam tape on the cowl to absorb any noise if they hit. I also tried ultra low profile screws but the hex cannot take 25 ft-lbs before it rounds out.
https://www.mcmaster.com/nav/enter.a...tnum=97050A141