Wayne, altho you've made up your mind I'll chime it too. Until I decided to keep it, I was going to sell my early 70's D-18 for $850 and it is in much better shape.
If you find another one some things to look for are the saddle height and need for a neck reset (every Martin gets one at some time in their life), the crack in the top next to the pick guard (the pick guard will need removal and replacement with a stick on one), and the possibility of a little "belly pooch" on the lower bout. QC wasn't as good at Martin in the 70's - look the guitar over very carefully.
Unfortunately most pawn shop owners really know the value of the things they sell. The days of finding a dusty pre war herringbone hanging in some little hawk shop are pretty much over. This one was way too much.
If you really want a Martin you might lurk over at the UMGF and check out the buy and sell
Unofficial Martin Guitar Forum