Yes, the "easily make one" is probably true. However, as I mentioned in Reply # 2, the 358350-S100 clips (identical except no "step" shown in the generic Ford Standard and Utility Parts Catalogs) were used as far back as 1954 (actually earlier on Ford Trucks), in such applications as 1949-51 "Starter Cable to Frame" on Passenger Cars, "Heater Switch Wiring" on 1957-59 Passenger Cars, "Headlamp Wiring to Grill Panel" on 1959 Passenger Cars, etc. This clip was still shown as available in the 1975 "Standard and Utility Parts Catalog" but not in the 1981. Thus, there were obviously many more application where it was used after 1959 in order to justify its being around for such a long time.
As I mentioned in my Reply # 2, this 358350-S100 appears identical to the 358352-S, except for possibly the "step". This step could easily be added, then the clip restored as Jeff me3ntioned in his Reply # 11.
OR............................................
You could go to NPD's site and purchase the one shown in the attached picture, Note that it is shown with the step, rubber coated, etc. This 358350-S clip is shown for a Thunderbird, but sure looks identical to me. This goes back to my comment in Reply # 2 that the 358352-S number was either an Engineering Number or an Assembly Line only Part Number.
I don't know about others, but my time is sure worth more than $1.94 an hour for the hours (and materials) needed to "easily make one of these".
Hope this helps.
Bob