So no IFR probe or is it only for now and it'll be installed later? If not then it will serve mostly in the air-to-air role I think.
It looks like the probe can literally be bolted on from the below pic.
And if I look closely at the comparison image Deino posted, I think I see the square panel present in the new batch:
The IFR probe is useful regardless of the mission. It greatly adds to the loiter time in CAP and Escort sorties.
From what I've heard, one squadron will be deployed at Kamra AFB under the Northern Air Command. Rafales are only expected in the North. But the other squadron is headed South, where the PAF also has to cover the Navy and the coast. So the IFR probe would definitely be needed there, even for CAP.
With that said, with or without the probe, the primary role of J-10s will likely be Air to Air. I expect the same for the Block IIIs.