Scott I think those 70 mach 1 moulding would be easy to make or find replacement out there as most cars are missing them & if car has been apart or painted they got tossed as body guys never watched where they go & are easy broken (very thin) when removed & you don't use the door bottom rubbers when these are used. I never heard that not all 70 mach1s used them & where did that info come from?
Ed, here's the evidence that not all 70 Mach 1's used them:
From the Osborn 1970 Mustang Body Assembly Manual, p.13 "Front End Section" that mostly deals with blackout. This black plastic strip is illustrated in Figure 2 and Views F and H as item #6. Item 6 is described as
"(DOZB-63101B62) filler - 1 reqd. each side for Mach 1 only (DOZB)". This drawing is dated 11-18-69 and supersedes the drawing from 9-20-64[sic] [probably a typo for 9-20-69].
The note at the bottom is the clincher.
"Effective with CZY1-DR-527839 - added item 6, (DOZB-63101B62) filler, revised Fig. 2 and View "F". Added View "H"."As this is effective part way into the model year, earlier production Mach 1s would not have been built with this part.
There's more in the second part of this note about another rolling change:
"Removed item 3, blackout paint from cowl top area, removed view "A" ". This indicates intent at least to stop blacking out past what appears from the illustration to be the firewall pinch weld.
It's funny what you point out about that bottom door seal (the rubber one that attaches to the door). Page 58 of the same source states for this item (5) -
"NOTE: Delete when RPO rocker panel mouldings are used." This drawing is dated 8-15-69, superseding the one from 6-12-69. I didn't know this and don't quite understand the rationale for deleting it as the rocker mouldings sit flush level (or slightly lower) to the door sill. I can see where adding the plastic filler strip over the sill might interfere with the rubber, but without it the sill/door interface is identical to other models. Yet, this note is included in a drawing dated before the inclusion of the plastic filler strip, so what to think?
There's a little meat to chew on ...