He just shook his head about the bike. That decision had been made. He would wait. There was also something in him right now that didn't want Mary to think he was overly attached to the vehicle. He didn't want her thinking that the bike was more important than her somehow.
"Alternate reality brother." Johnny laughed a bit, then stopped suddenly. "Oh. Shit. Rob?"
He looked at Mary. He didn't know if she was going to be happy with him in a moment. He tried to sort over the kinds of details that he'd said to Rob, and the sorts of things that might come to light if the kid ever put two and two together, which he likely would, since he was not only a Winchester, but had also seemed like a really really smart guy.
"So it's too big of a coincidence that you have a brother named Rob and I met a guy named Rob and we talked about time travel and faces being familiar but it not being the exact right person." He gave her a bit of a sheepish grin, hoping that she wasn't too mad and he hadn't fucked things up too badly.