Regardless if AIM260 is integrated into F-16s or not. Pakistan will not be granted next gen / long range AAM i.e AIM260.
Its basics of understanding geopolitics, despite 'favorite field marshal', we are in no such significance for United States as India is. AIM260 will be for US airforce, some NATO allies, Israel and maybe any one of the GCC nations against ridiculously expensive deal.
F-16 block52s and AMRAAMs were sold to us at height of Pakistan - US collaboration when Pakistan was a sole supply line for US forces in Afghanistan. We were a must partner for them. Yet again those were sold as "defensive capability". No stand off air to ground weapons are allowed. As part of agreement, we can't integrate any air to surface stand off capability. Even 120C were sold as defensive means to protect against any air attack.
I don't see even any remote possibility of PAF getting AIM260. However, yes 120D can be sold but not anytime soon.