Really
Pavlos or someone else who knows Greek well should comment on this.
But it certainly doesn't seem likely the
Dorian has a meaning of "golden" from Greek, because the normal Greek word for "gold" seems to have been
chrysos (see the name
Chryses in this site's dictionary.)
The "a gift" interpretation comes from assimilating
Dorian to the Greek word that meant "gift" which forms part of the base for names like
Dorothy and
Theodore. But I would imagine that if there was any good evidence that the name of the ancient
Dorian tribe was actually connected with that word, this would commonly be explained by the more accurate books on name origins today.
It is probably that the tribal name of the Dorians is simply so ancient that no one knows its original meaning beyond "tribe from the region of
Doris." Really ancient place names often are simply going to remain forever unknown in their origin.