I don't think so;
-We will keep on producing extra BLK IIs till 2021.
-Simultaneously we will procure second hand F-16s as many as we can.
-We will also upgrade existing fleet of thunders (BLK II) with new goodies most prob AESA upgrade.
-Then in 2021 we will get a fully operational squadron of BLK III thunders.
PAF will already be receiving used F-16s , BLK IIs and later on BLK IIIs thus no need for a new platform like J-10.
2021:
A decent fleet of;
-(16-20 JF-17 BLK IIIs +more on order
-(150 JF-17 BLK IIs)
-(100-120- F-16s)
-(20-50 ~ Mirages).