I'm not aware of any of the Gulld factories including shims under the fretboard extension as part of their standard build specs. Shims typically only get added when the neck is being reset, and the only Guilds I've seen with shims are the ones that had had neck resets done.
There are two kinds of neck resets (both involve removing the neck) and two kinds of shims.
The most common is where the neck angle is adjusted, and the headstock end of the neck is angled back. This involves reshaping the dovetail joint and fully reseating the neck as it was originally. In this instance a ramped shim is added to the underside of the fretboard extension (it's wedge-shaped like a door-stop) with the pointed end under the 14th fret and the thick end under the end of the fretboard extension.
The other kind of neck reset (less commonly seen) involves no change to the angle of the neck. Instead a shim which is the same thickness for its full length is glued under the fretboard extension and the neck is reseated a few millimeters higher than it was originally. This repair works but it means a tiny area of the guitar body previously covered by neck heel is now exposed.
In terms of the work you had done and what you paid -- IMO the price you paid was quite reasonable, but an experienced luthier who has done his or her fair share of neck resets would have likely done a neater job cosmetically, and charged more.
I imagine this was your furniture repair person's first attempt at a neck reset, yes?
Good info here:
http://www.fretnotguitarrepair.com/repair/acoustic-guitar/neck-resetting.php
As others have said, enjoy the guitar -- you've just extended its life by a couple decades!
You certainly got a lot for your money. At this point, the looks of the guitar are not what it's all about. It's the sound it puts out, the tone. And it's a burst. 
As you say, it's all mojo. It's like a rapper with bullet scars, it's got cred! 
