They will not sound the same to anyone with any degree of training and/or ability. There are too many variables. "Identical" is extremely hard to come by in such a complex system.
With organic materials such as wood, just because the back is, for example, even as specific as Brazilian Rosewood or Honduras Mahogany and the top Sitka Spruce, is no guarantee the grain (variations in size and density largely from seasonal growth but also includes anomalies from mineral concentrations such as commonly visible in Curly Maple, Birdseye Maple, Quilted Maple, Tiger-Stripe Maple , etc ad infinitum) is at all similar. These profoundly affect tone.
If we step away from just "guitars" and go to simply "stringed instruments" we can approach a very instructive example in this matter. Stradivarius Violins sell for millions of dollars and for good reason - they have yet to be duplicated despite extreme (and expensive) attempts by craftsmen, history scholars, and scientists to do so. This "Holy Grail" has led to searching records for where the specific woods were grown, bought, stored and treated as well as finished, and also the application of some extremely expensive and capable scientific instruments.
For example, deep Composition Analysis (at the molecular level) discovered that for whatever the original reason (sound? look? vanity?) precious gems were ground up and mixed in with the shellac. Attempting to duplicate these processes has so far failed to reproduce a Stradivarius.
The opposite approach has been also tried - Spectrum Analysis of the sound and the creation of synthetic materials (which can be tightly controlled) along with specialized shapes have made very sweet sounding violins but fall very short of duplicating Stradivarius.
Is this just Musician Mysticism with no measurable validity? I think not since I was trained by a 3rd generation Luthier from The Netherlands to restore fine violins. Although I'm afraid the most expensive I ever got to restore was an order of magnitude cheaper than a Stradivarius, I can most certainly hear the difference even within a workroom. In an actual performance hall, Washington DC's DAR Constitution Hall, with no microphones, for example, I experienced Isaac Stern playing a Stradivarius and was utterly astounded that this little wooden box was louder by far than the entire orchestra behind him, and the tone was so beautiful it made one want to laugh and weep at the same time.
This brings to issue the final variable - the player. Isaac Stern was a true Master of his craft in that empirical sense of someone who studied and practiced and played until it became so-called "Muscle Memory", instinctive. To bring this aspect down off Mt Olympus, the difference in tone that comes from a guitar player's experience does not cease just by learning how to not make the stings buzz on the frets. Playing from sheet music also progresses from the "See the dog run. The dog can run fast" level to instantaneous fluidity, just as Math can look like hieroglyphs until a person has used it enough that it becomes language... a language that speaks to you upon sight.
There are no identical instruments or players... just similarities.
