I agree with Adam's appraisal. At the low end a grand each if relatively solid. If they're rust buckets still look into a fair package deal. Un-cut dashboards are tough to come by, as is the afore mentioned year-specific grills & taillight panels. Not to mention all the nuts, bolts, clips, etc. that always break your b*lls.
And as if I need to say this, the fenders alone are worth about $250-300 ea. if they are usable. Nice ones with no rust or patch panels? Easy $500 apiece, maybe more. `67 fenders have no side marker lights, which make them a headache-free swap onto the other years. If either one ( or both....) are as solid as your Duster, grab `em if the price is semi-reasonable. I know I searched for over a year to find something restorable here on Long Island. You have the space. Sit on them until you decide what to do.
And of coarse, PICTURES!