Hi! We got an upgrade at the GF, to Royal Palm Concierge from a lagoon view room, but that was because they decided to sprinkle some pixie dust on our Disney wedding/honeymoon trip.
Now that we've stayed Royal Palm, we realize that we want to stay in concierge on every trip, so we would definitely make sure that we paid the extra to guarantee getting concierge level. I wouldn't count on an upgrade - we loved the main building concierge too much to risk maybe getting a regular room. If you really want it, definitely just pay the extra money and have that guarantee.
Cheers!
Heather W