Need ID on Shiny Noctowl (Pokemon) Cel

[Sui Kune]

On behalf of a close friend, I've been searching for the ID of her Shiny Noctowl cel. And so far I've come up empty, even going through screenshots of every episode from its introduction to the last episode that used cels (I believe either #262 or #263). It's been driving me absolutely nuts, so I come to you guys for help.

Here's the beauty, and here's a sequence mate she tried for but unfortunately lost. It's a standard-sized cel, and I believe Sensei identified the 209 as the cut number. You'd think such an unusual Pokemon would be easy to pinpoint, but nope. Pokemon is huge, too, for all we know it could be a commercial cel or something, or from one of the obscure specials.

Any help would be greatly, greatly appreciated!