Hi flashran, welcome to the forum. :wave:
Never having had the dash off on my car I am not sure if the Fiat clips are "universal" or unique to the 500 so the only suggestion I can offer is to contact your local Fiat parts section or you could email/phone chris@souls who is very helpful to forum members.
Failing that you can wait until RUI reads this as he will almost certainly have one in his desk drawer.