Your useful post.
A retired Indian army officer who served in J&K during the heydays of militancy, when veterans of Afghan war also came to fight for jihad in Kashmir, told me that in his experience, he could not find a single terrorist who was hailing from either Gilgit or Baltistan. Most of them were from south Kashmir, PoK or from other parts of Pakistan. So India could try to liberate these areas first than PoK.
This relates directly to the history of the gradual building up of the old J&K princely state. From its core status as the fiefdom of the Raja of Jammu under the Sikh Kingdom, it expanded into Kishtwar and the hill provinces outside the Vale, then, leaving the Vale under the direct rule of the Lahore Durbar, the conquest of the-then independent kingdom of Ladakh, the conquest of Baltistan, and finally, the disastrous expedition into western Tibet where Zorawar Singh lost his life.
Gilgit never figured in this.
It was only after the humiliating experience of a British Army officer being ordered out of the principality of Chitral that the British took interest in the most outwardly part of the region, the Pamir principalities. The British and the J&K Maharaja's forces attacked these principalities jointly, and annexed them. Initially they were permitted to be annexed by the J&K State, but almost immediately, on the grounds that Russian exploring parties needed to be continuously monitored, Gilgit, constituting all the little valley principalities of the region, was leased by the Crown Colony from J&K.
The result is that there was never any connection between the Maharaja and these regions. When Independence came, they quickly revolted (soon after the Sudans of Poonch revolted in October 1947) and by November, had declared that they were free of Maharaja rule.
The people of Gilgit never felt any affiliation with the people of the Vale, who were in any case not in any situation to deal with other peoples in any circumstances of equality at that time. As a result, they feel no urge to get involved in the Kashmir movement.