I wouldn't add sticker on the outside. If I like to use typewriters, it's in part because they're a part of an other time, relics from the past; even if they're a part of my actual workflow in 2026, I tend to aesthetically conserve them, not unlike museum pieces.

But I would totally add something on the inside, and I think it's a wonderful idea! I love to find ex libris in the old books I buy (but nobody put an ex libris on the cover), I think it would be cool to find an ex thesauro (I prefer this form over "ex collectione", it feels more classic to me but I'm not a good Latin writer so I may be wrong). It's like a little gift to the people who will own my machines after me, as they would know more about the history of the machine.

Thanks for the idea!