I was wondering this because I saw videos from JP where certain 13-star drops had to be identified (Rappy Egg 13 star being one of them).
I have yet to get more than two, maybe 3, total 13-star drops since I started playing. It would be AWESOME if I got a Rappy Egg next PSO2 day, but it'd really take the joy out of the moment if it dropped with Wind or Fire, or basically anything other than Light.
Similarly, if there's even a chance at Nemesis or Slave weapons dropping unidentified that'd be a GREAT place to dump meseta on an enhanced appraisal I think.