For jewelry, trade or whatnot?
It doesnt seem so. Whether or not they knew of it is controversial.
Only what they found easily. I never heard of them mining or doing any sluice/panning for gold.
Gold doesnt have intrinsic value to humans like food…
No, but it’s shiny, and it stays shiny for ever in human terms, and many cultures the world over have valued it just as a rare decoration that other people will hand over necessities for because they in their turn want some decoration and it’s hard to come by.
Anything shiny on the plains would give away location to a raiding party.