Those look like the ones used in the trunk but with the rubber coating. Not what I've found on Fall 64 San Jose cars as shown below
I had questions on this clip for both my SJ 66 Hardtop and SJ 66 K Fastback, they both came with 372047-S100 clips as shown, the K uses an additional clip for the manual choke cable. The clip "may" also retain the convertible power feed cable.
There is one more clip of this type used on the radiator support by the battery replacing the plastic strap, 376914-S, again San Jose only - unless someone with a 64-66 Metuchen or Dearborn Mustang, or 64-65 San Jose Mustang wishes to contribute more information about these variations.
I did find that my 64-66 Hardware Spreadsheets had documented this variation, but I reworded the application for clarification.
Jim