Searching on Google ( for missing women in the Gallup area, in this time frame) brought up this mention of a search for a lady known to be suicidal, in early February 1990, a Gallup resident who headed up to the hills north of the town.
The few details given ( for example, that she gave away her HOUSE & car to friends, prior to disappearing) give me the impression that this person was probably older than the estimated 17-24 year range of the unidentified deceased but I’m guessing.
One would hope that this missing Gallup resident would have been considered as a potential match when the female skeletonised remains were found in 1993.
( I can’t find any more information about the missing person….she may of course have been located)