Acoustic Guitar Construction

Voice of inexperience here. But I am a trained musician.

I would be surprised if the accuracy you are describing is not close enough.guitars are tuned to equal temperament which means somewhat out of tune in every key.

I know it is different for every note. But do you know how much (cents) off-pitch is involved in this temprament?

Short answer, No.

Temperament refers to the fact that pitch, as you hear it, is relative, but obviously on an instrument like a guitar where frets are fixed there is no opportunity to vary a note according to the key you are playing in. I'm not very good at explaining, I'm sure there are some good expalanations available but for instance if you tune the guitar whilst fretting an E chord so that sounds perfectly in tune, but then try to play a tune in D, for my ears the F sharp on the second fret of the high E string needs to be lower when in the key of D than in the key of E.

There are different tempering systems which are still used in so called 'period performance' when playing wetern baroque music.

Tony Rice interestingly mentions his old Martin doesn't play well in tune and he will tune it differently according to the key of the tune. He mentions in another clip that his santa cruz has very good intonation.

I looked it up, but the differences between the Just- and Equal temperament can reach up to 1 cent.
(exc: In C major the A4 is 436.05 Hz vs 440 Hz.)
This FWIW
Herman