It is, efffectively, damage, so I think that is the best thing to do, although some folk might disagree and would call it restored or repaired and want a discount for that.
It's a difficult decision, but having it photographed and illustrated here along with that information does help to keep everything above board.
I've been in a similar position, with a Lollipop which had a manufacturing flaw removed (a great gob of glass had landed on the finished item accidentally and spoiled it).
I thought I wouldn't be selling it, so it wouldn't matter, but somebody persuaded me to part with it, so the whole story had to come out.
Fortunately, there were records here to confirm what had gone on and the buyer was happy with my actions.