Theres nothing wrong with selling at profit
Theres plenty wrong with misleading your prospective buyers. They're getting something under false pretenses. The phrasing of the ad is carefully geared to be true, strictly speaking, but to give the impression of things that arent true. Never gigged - certainly he never gigged it. Not never gigged. Cost 2300 new - yeah, it would have, but he didnt buy it new. BKPs added "now" it sounds fantastic implies he heard it before it had the NBs in, which he didnt, but that statement is still not a lie; it presumably does currently, at this moment, now, sound fantastic.
The whole lot, while each part is true, adds to build a picture of him buying this guitar when MotE did, rather than a week ago, of him putting the investment in pickup upgrade, paying for the work to be done and carefully looking after the guitar, never gigging it, for that time period. An ungigged guitar thats had professional work done on it leads a buyer to be more reassured of the condition and reliability of the instrument, and to state or suggest these things where they arent the case or are ambiguous is deceitful.
If I were looking at buying the guitar off him, I would want mote to say something about this, because I would want to know that this person isnt someone I would want to buy anything whatsoever from.