I can’t find a thing about Mark Bennett having clerked for Thomas. He clerked for District Court Judge Samuel Pailthorpe King.
He is a Federalist Society member though.
Here’s something from the GOA opposing him.
https://gunowners.org/alert51618.htm
27 Republicans voted against him
Look at the yea/nay list. All over the map. Flakey and Cruz, Scott and Cotton all voted against him.