I want to give my thoughts on the finale to Lupin the 3rd part V, so, spoilers if you haven’t seen it. The way I interpreted the mask reveal was that it was intended to be more metaphorical than literal. You see, Lupin is a real showman, always making things more extravagant and theatrical than they need to be, even following rules of narrative, such as “show don’t tell” (e.g. the scene in episode 2 where he feels awkward having to explain outright that he’s protecting Ami from Marco Polo). His big speech in episode 23 was about how he sees his life as a performance, and he’s always excited to see how the next act plays out. And so in the finale, when Fujiko asks “What am I to you?” she’s explaining that the reason she left him was that she always felt that she was just another character in his story.

Rather than giving giving a speech, Lupin made a gesture which allowed him to step out of his performance. As such, the message he was giving her was “I love you, even when I’m off stage and out of character. Even when I’m out of the limelight, in the wings, in the shadows, I still love you.” And he did it that way because to him, actions speak louder than words.

That’s how I see that scene, anyhow. Overall, I enjoyed part V far more than part IV, and I think it’s one of the best Lupin III shows in recent history.