One option;
when things were cheaper, was to put the small 356 hood crest on the standard plain banjo horn button with two sided tape. Prices have gone up so what used to cost 50$, now will run you 100$ if you need to purchase both pieces.
the hood crest contour matches the button contour. Just grind smooth the tab off the back of the hood crest, and add two sided tape.
sample of when I ran an ivory horn button.
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Parts:
horn button in black or ivory:
https://www.vintagemotorcarsin...tton-black-or-ivory/
Small 356 hood crest:
https://sierramadrecollection....56b-60-63-356c-64-65