Chill down body. Have you forgotten how Iran's auto industry started? It was Paykan, Peykan with Joshan bumper, Paykan with Peugeot engine, Peugeot with Paykan engine (RD), and finally Samand.
They will test any possible combination and mutation of F5 to make sure they have mastered it and then when they are satisfied, they will come up with a new platform. You also need to consider the fact that out of all the divisions of military, Airforce is the most conservative one to try totally new and untested platforms.