You get a star in your file when you beat Another Code R, just like in Hotel Dusk. But I lost my original save and while it's a nice game, I'm not interested in having to play through it two more times to find out.
Honestly kind of cool how a game can have this little known about it in 2022, haha. Maybe I'll discover it myself when the time comes, but it looks like the answer might unfortunately be no.

The save file does get starred for some changes in your second playthrough, but IIRC there's no "True" Ending. Besides adding text skip/movie skip, I think a few puzzles get slightly altered, there arae new DAS messages, and the ending adds another still picture.