2 didgit/ is worth about 80percent of listed value for an unc in au; about 50 percent in vf/ef I am thinking...as it is a modern 20.00 you see
.. you will have to wait awhile for it to increase in "book" value...
That being said: a modern unc 20 radar..is selling for between 50 and 65 dollars (common 3 or 4 didgit) .. so a two didgit vf/ef should go for a little bit less..but not much .. maybe 40 to 50 bucks...maybe...depends on the desire of the collector buying the note.
in G/VG....its a keeper...not much market for selling in that condition...but Johnathon (lol) it is a 2 didgit..so all arguments as to "value" are truely in the eye of the beholder..and the "holder"...
I have a 1937 1.00 2 didgit..that is vg..and it makes no difference to me the "value" of the note; it will never be sold...traded for a better one maybe...but never sold.