At least the baby knew enough to bow. Bartleby wasn't going to comment on the fact --because smartassed comments in front of God? He was so done with that-- but he might have given the tiniest bit of a smirk upon his arrival with Loki. This was, of course, right before he fell down onto one knee, an action he did promptly and with all the respect due to his Creator. Despite past events and his own opinions, he had the utmost respect and love for the being who had created him and could absolutely obliterate him just as easily.
"My Lord," he said softly, after briefly looking over to his side to make sure his friend was going to do the same thing. He was taking no chances with Loki's temper.
It was a moment he'd been waiting for for years upon years, to bask in Her presence once again. Here now, he wasn't willing to relinquish it easily. It was as wonderful as he'd remembered and imagined it to be over the past two millennia. The feeling of being completely whole and loved once again. It wasn't something easily found in Wisconsin, especially when he'd thought She'd not been listening.
But they were here now, and for once they weren't the worst of the group. Bartleby didn't wish what Castiel had done on any angel, knowing that Her wrath could be nothing short of epic when She chose. Bartleby liked Castiel well enough, but he was glad that he'd drawn Her attention his way.