Dean's presence has much the same effect. Cas wakes to it; he basks in it. This is Dean as he was, Dean from before, in his own here-and-now, and so much better for it. At Chitaqua, this Dean's pre-war soul had been so out of context that Cas could barely look at him, despite wanting to very much. He stares now, greedily.
Dean blinks, taken aback by either the level of detail in his answer or his naked gaze, Cas isn't sure which. Both possibilities make him grin, even as Dean schools his expression and squares himself up. "You know when you are?"
"I suspect it's 2009." His gaze flickers down Dean's throat, and finds a conspicuous lack of amulet. "Late summer, at the earliest."
"You know how you got here?"
That punctures him. After everything Dean did to get his shot on the devil, Cas must now admit to having benefitted--presumably--from Dean's failure. His skin prickles with shame, which is ridiculous. This isn't even that Dean. Yet. "Yes."