Slant six engine EGR valve blank off plate?

I've made a few over the years.
If you can find a late 70s truck or van in a boneyard with a slant 6, many came from the factory blocked off especially the higher gvw models.....the B 100 or D 100 might have EGR but a 150, 200,250 might not. I know the v8s of the time were that way.