I couldn't tell from what I've read, did the Durango with the teenagers in it drive off, or did the police show up at the gas station and they were still there? To me, that would make a big difference wether I thought that they could have ditched any weapons or not.
All around, it just looks bad for this guy though. I'm not sure if his lawyer going around spouting off about how he is totally into guns and a gun collecter, etc. will help him look responsible and educated, or more likely the press will make him out to be a "gun nut" who was crazy and has a massive arsenal and was just looking for an excuse to shoot someone.