Which means he knows it, because he wouldn't dislike a name that doesn't tell him anything. There aren't that many names coming to mind and - he has to consider the portal (that he doesn't remember) and the statement about alternate dimensions.
This is clearly getting crazier by the minute, and Dick has a feeling it's not done at all. He sighs of annoyance as they walk into the elevator. "That doesn't stop me from wanting to know it. At all. In fact, I now want to know it more since it means I know you."