What you've got on is basically spot on...
HBT coveralls would've been de-rigeur also, and oily ones at that!
Or a lot of the recovery guys wore tankers gear, so tankers jackets, HBT's, boots (you've already got) or the Tankers Bibs... Althought the tankers gear is insulated and tends to be a bit warmer for summer do's. Mix n match I'd say... most of their gear ended up lagged in oil, grease and worse!
Helmet markings ida thought would be fairly minimal but Enigma will know the way!
The only thing i'd say is if the sunglasses aren't prescription...
back the truck over them
and get some period style ones Aviator copies etc or the round lensed wire rimmed type.