He brings up his hand, initially not in any way to pet. It's more a defensive thing because he isn't sure what would be construed as an aggressive posture here. Were he out in the wild some months ago he might have already pre-emptively acted. It's only that this is probably crew, probably not going to be incredibly hostile (he better the fuck not be wrong) that he doesn't do something in a rash effort to protect himself.

However, his free hand has pulled back the side of his coat where his holster is just in case.

Alright. So it's just... bumping his hand? What's happening here.

"I ain't sure about pettin' somebody I don't know... Well, with a few caveats." But those are a different topic and half the time he's paid those people to be good to him, so...