If there was a known history then they should have outed him well before anything major happened. The guy is a jerk and vindictive at that. I would doubt that he sold it for $1 though. Personally, I wouldn't give the guy any privileges since that's exactly what he's looking for. He's probably laughing about it.
If your club were to take the guy to court, the judge will ask to see a bill of sale which should have the name of the buyer on it. If it's found that the trailer wasn't the guy's to sell then it would be considered stolen property. This doesn't mean the club would get it back as jurisdiction ends at the state line. But it would be entered into the database and could be picked up if someone sees it. Lots of if's though. The trailer is pretty unique though so I think the chance of recovery might be higher then average.
I think it would be tough to build a CJ grill as there aren't that many CJ's around. Even YJ's are pretty rare. Might have to make it a TJ.