There is no conclusion in this article if you care about such things.
NGL, the quote below was a nice way to end the article giving all the data we have though
> So we may not know for sure what the Set animal is, [...] And maybe that’s exactly how a god of chaos within an ordered world would want it to be.
Unless you invent a time machine of course.
The value of a 'mystery head' may actually indeed have been the intention of the original artists. A '*'-char for Ra.