I'm not even good at recognizing people I actually know, but since Dave won't enlighten us, I'll start off with four guesses and some long shots.
In front I believe George Johnson is on our left. It's is almost surely Dick Voynow on the right.
The back row has Jimmy Hackwell on our left. Vic Moore, with the mustache and all the hair, is second from the right. The man on our far right, shown only partially, MIGHT be Bix; at least it looks a bit like his hair. It also might be Min Leibrook, although the hair doesn't look quite right. That leaves Hat Guy to be either Min or Howdy Quicksell, wearing what looks like a mustache.
Since the car is Open Job #2, Al Gande would not have been with them at this time, so he shouldn't be in the running for Hat Guy.
It would help to know if Hoagy took the picture (it is his car, after all), or if the missing Wolverine could have been the photographer.