[MMSe]

Thanks Gusteau, that's good advice.
When I ate lunch with the vice president, he did say that the fraternity has "unofficial recruitment", which is where, he said, they are always on the lookout for new members and for recruiting guys even after "official" rush ends. So that does make me feel better about calling them up, especially because one of the guys I liked talking to was the recruitment chair.

And after I met with my friend who is the rush chair for my original backup and explained all of this to him, I chose to defer on their bid. I told him straight up that I was still considering joining another fraternity, but he seemed to indicate that was okay. So I have a week to change my "defer' to "accept" for this one, but it seems like this semester I can just hang out with both groups and see which one I fit in better with.