The VINSON is a west coast ship now. I drive by it every day. She was on her way to San Diego for a port change when Haiti happened (I was there, as well, and landed her many times) and was delayed there for several weeks, then continued on to SD.
According to VFA-81's website, they're part of CVW-17, which is out of Lemoore, again, a west coast wing. Yes, -81 is out of Oceana, which I wasn't arguing. What I was saying is that they are part of a West Coast airwing, hence the Nx tail code.
It's not abnormal for squadrons to be in different locations than the Wings nowadays. After Miramar was "lost" to the Marines and Cecil went away, everything went to Whidbey, Lemoore or Oceana for TACAIR. I work next to a squadron (helo, in this case) that's number is even, which denotes it's an East Coast squadron, but it's actually on the West Coast. The reason was that one of the CVWs (it might be -17, not sure) moved after the squadron was named.