First thing I thought was who the hell plays on the 24th fret?
A few factors to consider. Strings, old/new? Action at 24th fret? Is the buyer playing the harmonic or the fretted note? Do the other strings intonate correctly up the dusty end? Neck on the wonk?
It's feasible that the 24th fret could be in the wrong place, unlikely, but possible. It's also possible that if the action was a bit high at this point, simply depressing the string might throw out the tuning.
Given the scale on these is (I believe) 34", you're looking at a fretted note at the 24th fret to be c.8.5" this high up the neck. If the frets are wide/jumbo and haven't been crowned correctly, given the shortness of the scale at this point, this could throw out the tuning/intonation a little. A little. Millimetres, or part thereof, will make a difference at that point, no significant but a difference.