Sometimes Yamaha used duplicate model numbers on their FG models. Sometimes wrong specs get copy-pasted while trying to sell these guitars. If you think you’ve just bought a new FG and it turns out to be a sought after vintage instrument it seems a manageble problem. The other way around is a bigger problem and that’s what you see most.
An example is the vintage early 70’ies FG440 with the wanted Jacaranda back and sides:
Must be disappointing when you get this:
I saw a new FG440 offered with vintage specs and saying it was “white label”. And yes it is, but not the kind of white label we are looking for.
Luckely sometimes the differences are so big you almost can’t go wrong. Look at this fantastic 1974 FG700S:
It came with the black label.
And sure differs from this current FG700s:
Take a look at this 1972-1974 Nippon Gakki white label FG340, a Japanese market OO type guitar with rosewood back and sides:
Different from this export market 1977-1981 Made in Taiwan 3-piece mahogany back FG340 in dreadnought style, or Jumbo as Yamaha kept saying:
You can even find a recent FG340 (pic from internet):