It _is_ one of the most reasonable guesses out there so far. The next best one, the ampersand, was kicked out by Claude for now somewhat obvious reasons : ).

But yeah I do agree it might not be likely since that could result in overlapping themes for the solutions. Still, let's not forget the "14" and the "8;" they weren't exactly the easiest numbers to decipher given the size of the glyphs. But I agree, that clef is rather...not clef-looking ; ).

Here's a brainstorm of a few the things G5 could possibly stand for, symbols or otherwise, in my head right now. Some are repeats and I've noted them where my memory permits (too many messages to remember now : P). Maybe they'll help, maybe they won't, probably they won't ; ), but hey, who knows.

8 (repeat)
J (repeat) -- looks more and more reasonable to me
8J (combination)
J8 (combination)
infinity symbol (repeat)
infinity symbol + J (hehehehehehe, anyone get that? : P)
J + infinity symbol (combination)

And here's some strange ones from me : ).

bird? (not likely)
a type of flower?
a fountain?
a bugle/trumpet/soundpiece of a Victrola of somekind?
waves? (rotated, but unlikely)

And my personal favorite: a banana peel? : P

That's all I can reasonably think of for now.