Dear Gorgias;
You asked:
I thought you didn't believe in this stuff. . .
My answer is, no, I do not believe that signs and symbols were carved in order to mark a treasure cache. I do however, believe that certain signs and symbols have a historic significance attached to them and they reflect a thought process, or an idea, of civilizations past, and in light of this, to me signs and symbols are not the means to an end, rather they are the ends unto themselves.
In order words, the signs and symbols do not lead one to treasure, rather the treasure is the sign or symbol itself, my friend.
Your friend;
LAMAR