At the opposite, I tend to "unfarkle" my bikes : stickers are removed before they become olds and leave marks on the plastics, then right mirror, blinkers, canisters and all these unuseful and so heavy parts.
The only added parts allowed (on my bikes) should come from the bike manufacturer if possible, in order to stay as close to stock as possible. Anyway, reversibility to stock state is a must for periodical inspections (every 2-3 years here).
When I get a used vehicule (car or bike) all the previous owner farkling is usually nothing more than someone else garbage. Now about selling a farkled bike ... never had any pay-back for farkles, except as a selling argument.