Mutt, of course you may, and I am not taking offense. This discussion is a bit like the four blind men who, upon coming upon only the trunk, tail, leg and side of an elephant said that an elephant was like, in order, a fire hose, a rope, a wall, and a tree. You and I are viewing the question from a different perspective- you are saying, in effect, don't get hung up on the type of finish on the top of a guitar- there are so many other variables, so that one variable is impossible to quantify," and I am saying "True, true- but IF one could hold those other variables constant, the
sound or tone of the guitar would change if the top had either a matt or a gloss finish, because a gloss finish requires more material to be glossy." Please note, too, that the OP asked about the
differences in sound, and mentioned relative quality almost in passing.
But, please notice that I agreed with your point that the top finish is not the primary thing to care about, that "the sound of a guitar is the sum of all the parts and not just the top."
Of course, Yamaha does not use rattle cans to "paint" guitars. From a standpoint of final finish quality, there is nothing wrong with rattle cans- I have seen some damned impressive work done with just rattle cans, and a guitar is small enough of an object that one can achieve excellent results with cans. Yamaha simply goes with the production method because it is more economical than cans (obviously.) Of course not everyone uses the same method to finish anything, but the demonstration is still valid- I suggested rattle can enamel because more folks are likely to have a can of that stuff around than any other finish material/application method.
Any high-build finish material (which includes enamels, lacquers, polys, but excludes pure oils) will require more material be applied if one desires a higher gloss. Whether one will achieve the high gloss with a material that "settles" to a high gloss, or by buffing, or both, more material is required. "High build" refers to the relative amount of material that is or can be applied in each coat, by the way.
(As an aside but related point, "buffing" is usually NOT simply abrasively removing material to have a consistent, smooth "top" of the finish- it is done by using heat to partially melt the finish so it flows into that smooth top- and this is done with almost all finish materials- lacquer, enamel, polys, even "danish oil," which includes a hefty amount of varnish in it. Even hand-buffing an oil-finish uses heat the same basic way, the main difference being oils don't solidify as hard as high-build finishes.)
NOTE: In keeping with my pledge that I speak from personal experience, I have removed finishes using scrapers, steel wool, caustic strippers, heat guns, wire brushes, sand paper, blasters, lacquer thinner, razor blades, fingernails, and stern looks, applied synthetic enamel, acrylic enamel, acrylic lacquer, nitrocellulose lacquer, polyurethane, boiled linseed oil, raw linseed oil, tung oil, danish oil, and finished (or, in most cases, re-finished) cars, motorcycles, bicycles, oak table tops, Hammond Organs, lawn mowers, hubcaps and wheels, solid-body electric guitars, hollow-body electric guitars, and even
acoustic guitar tops!
I knew a guy- he played mandolin in my now-defunct and un-lamented bluegrass band- who built mandolins. His instruments, when complete, were wonderful-sounding, indeed. The "trick" he used was he
wound not finish the top until after he had played the instrument, usually for months- he would continue to tune the top by sanding it down here and there until it sounded it's (presumably) best. Only then would he put a NCL finish- usually glossy- on the top. Basically, he was taking this whole "tune the top wood AND finish" to it's logical extreme. They sold for, literally, thousands of dollars, but I think he may have built a grand total of about ten instruments before the reverse economy of scale finally caught up to him, and he realized he would starve to death if that would continue to be his main source of income.