Well, there's only one other thing that he can do to prove to Thor that he's the real Steve Rogers, but he doesn't feel like he needs to pull that particular gambit, thankfully. He's hoping to keep that one a secret from Thor as long as he can, because he knows Thor feels possessive over it.

"Great." He nods, solemnly. "But I owe you a lot of explanation, once we're through with this."

They absolutely have plenty of time to talk later, Steve can almost promise that, and if not, then Thor won't even remember this place.