www.stangparts.com is the only "junkyard" I would think has black interior and they aren't cheap. I seriously doubt you'd find black interior at a local U-wrench-It.

My suggestion is to buy the black dash, door panels, seats, and other high wear areas. Dye the remainder of your interior black using a high quality dye. You may actually be better off finding a local interior shop to recover your seats, depending on how much genuine black seats cost.

We spent way too much money purchasing genuine black interior parts for my old '87. If I did it over again, I would have dyed the parts that do not get much wear.