The tape used on the 70 Mustang door sill does have a Ford part number - ESG-M3G58-A - identified on the drawing as 3" X 38" (ref "1970 Mustang Electrical Assembly Manual" pg 36, dwg E0-505-1, item no 7). The same Ford part number is called out in the "1966 Mustang Electrical Assembly Manual" pg30, dwg E6-8165-1, item 14, for the same purpose (Ford is known for not changing too much).
Be advised that on my 66GT Fastback, that tape is black on top and black on the "sticky surface" (not a technical reference but one that should be easy to understand). I looked years back.
Here is one source: https://www.deadnutson.com/assembly-tape-assortment/
The tape at Dead Nuts On is shown with a white sticky side. It is not identified as an exact Ford equivalent.
Unless Ford changed the supporting document to allow both a black or a white sticky side, this tape "may" not be accurate. Note: AMK supplied tape also is white on the sticky side. It is also not identified as an exact Ford equivalent. (I have a unopened package of AMK tape, B-11665, and it has a white stick side.)
Jim