Highly unlikely to happen this year thats for sure...maybe by next FEB when 2 more B 777s arrive.
The extra cargo carrying capacity of the B 777 too will come in handy for PIA versus what the A 310 can carry in its belly.
I remember reading many years ago that lots of Japanese and Chinese tourists fly PIA via ISB from NRT
to KATHMANDU-NEPAL !!!
But really is demand that big to justfy replacing the A 310s 170 seaters with 327 seaters B 772s??? I would prefer it if they flew the KHI-ISB-PEK
route instead 3 times a week with A 310s then do twice weekly with B 772s!!!