As Ralf said, it would be very difficult to find an available F-30R like Simon's from the years when Guild was still making them with ebony boards, black headstock veneer with crown/chesterfield inlay under the logo, and Grover tuners. It'd be the old 'needle in a haystack' to find one for sale and in good condition.
I think you'd be happy with a new F-30R. If you really feel the need to make it look closer to Simon's guitar, you can always use something like Fret Doctor or Roché-Thomas Fingerboard oil to darken the fretboard without dying it. I've used both and they do a great job. And you can easily change out the pick guard for the older style like Paul's. The new F-30R comes with Gotoh tuners, and again, you can switch them out for Grover 102C to be the same as his. With a little effort and not much of an extra cash outlay, you can get it closer to his guitar as far as appearance. The only things you wouldn't be able to duplicate are the black headstock overlay with the crown/chesterfield inlay below the GUILD logo, and the special truss rod cover with white edge, which isn't the typical Guild shape. But as you say, and I'm pleased to hear, your main concern is tone and playability and don't think you'd be disappointed. But guitars can vary, so just in case, order from a vendor that offers a no-hassle return period.
Not long after getting my F-130R, I changed out the pick guard with the old style and replaced the tuners with Grover 102C. The fretboard is already pretty dark...close to ebony, and the guitar looks great. But best of all, it sounds fantastic and plays like a dream. Just to show you what a couple changes can do, here it is before and after the new pick guard and Grover tuners.
and a couple more....
DC