I don't think there's such a thing as being based on Block 1, Block 2 etc. The whole idea behind blocks is that you can upgrade from one to another fairly easily. Also, you're kind of forgetting that the block 3 wasn't even a thing yet, you can't base something, on something that doesn't exist. Don't be surprised if you see the Bravos get upgraded to Block 3 standards effortlessly.The PAF intend to use the B model as a fully combat capable tactical fighter; however, as I've mentioned before, it's not just the hinges where there has been short sightedness. The B model should have been based on the Block III configuration, and not the Block II specs. For instance, the B model lacks the dedicated pod hardpoint on the starboard intake, which already hampers its CAS and strike capabilities. It also uses the previous UV based MAWS rather than the new IR based MAWS on the Block III. Although some of these specs could be addressed in future upgrades, along with an AESA radar, I can't see the PAF making full utilisation of the B model in its current configuration as a tactical strike fighter, or even dedicated special purposes platform (SEAD, ECM, ELINT, etc). It seems the PAF jumped on the twin seat bandwagon only when there was considerable interest from potential customers, for years it was saying it didn't need a twin seat version, rather than making full use of the potential from the platform.