I am not sure if they 'pitched' anything to PAF. The tour of the factory/business representatives would've been a casual meeting/photo op. Pakistan can ask from China what ever it wants, and China would be happy to oblige.
Think about this, while the GCC nations can easily source the Rafale/Typhoons/Tornadoes/F-16s and the M1 Abrams etc from the west, they may never get the stealth aircraft from the US (due to Israeli shenanigans) and Europe doesn't have any on offer. Which means, Russia or China is left for the 'low RCS/stealth' aircraft, and with Israel to receive the potent F-35s and no one else in the 'Muslim' region (not counting Turkey here) having that capability to strike back, GCC nations would definitely want a strike/fighter aircraft that can give them that insurance. They have the money, all the money in the world. If PAF is able to field two full squadrons (36-40 aircraft J-31 type), then GCC would, too, be willing to purchase these from China. That helps the Chinese firms grow their market exclusively, in a region where future Chinese interests may lie.