Yeah, I noticed that a while ago, but I'm not sure exactly whose fault it was, because at IMDb.com, where they do cast lists for individual TV episodes, they show the doctor's name as "Wilson." So either a prop person put the wrong name on the door, or maybe it was a Reeves mistake or a mistake in the actual script, and they decided to keep "Wilson" as the official character name. I know they were on a tight budget, so maybe they knew about the mistake but just didn't bother to retake the scene or redo the brief shot of the name on the office door using a "Wilson" sign.