I remember checking into this mystery molding a couple of years ago. Agree the early '71s had a lot of pieces with a limited appearance. My early-built Mach 1 (9/21/70) has the metal sport lamp sockets, fender rear upper filler/splash shields, fender and hood rear moldings, and the padded dash molding (What was left of it). Some earlier than mine had chrome sport lamp housings and a woodgrain panel on the front section of the console that matched the woodgrain on the center instrument finish panel. So lots of unique pieces on these early-built Mustangs. My late build '71 (7/28/71) had none of the items mentioned above. Most of these were running changes, making them difficult to track down. The rear upper fender shields, rear fender, and hood moldings had "not used" after dates in the Master Parts Catalog (MPC). But, since these cars were not built in consecutive serial numbers, there is the always present fuzzy before and after areas on these changes. Others, like the chrome sport lamps, woodgrain console panel, and padded dash molding, quietly disappeared with no fanfare or change dates.
I checked the entire soft trim section and the body section pertaining to the dashboard and padded dash area in all my early parts catalogs. Nothing indicates that the molding was ever available separately or had a service part number assigned. The MPC's final edition (5/75) shows two different part numbers for each '71 color offered. The listing indicates, "Includes mldg on the forward edge," and the other, "Less mldg on the forward edge." I checked the 6/71 MPC microfiche card listing, which shows the same for both pads. The '72 listings only show the non-molding version.
In '76, the dash pads that included the front molding were discontinued and replaced by the "Without" version. Then in '77, Ford, believing there wasn't enough confusion in the parts catalogs, replaced all the '71-72 padded dashes with "D3ZZ" '73 Mustang numbers. The only holdover '71-72 color was the D1ZZ-E green version since the '73 Avocado did not match the earlier green interiors. By '85, all the dash pads had been discontinued except for the '71-72 D1ZZ-E green version and the A/C, non-A/C for the '69-70 Mustangs. Surprisingly the '69-70 versions remained available until the early '90s, while the sole remaining '71-72 D1ZZ-E green was discontinued in '86.
Since most members here are probably not the original owners of these '71-73s, the above-mentioned unique early '71 pieces were probably already gone by the time your Mustang called your place home. By the time I acquired my early built '71 in 1981, the rear hood molding was gone, the rear fender moldings were in such bad shape they might as well have been gone, and the padded dash molding was crumbling like dried cake icing. These were daily drivers when new, and sitting out in the sun was not kind to these now-pampered garage-kept family members!
If someone were to figure out a 3D program for these, there might be a market for them. With so many of them gone and most owners unaware of them ever being in the car, it would be a toss-up on the level of interest.