But wasn't there a rumour than regardless all competition and rivalry SAC is producing certain parts of the J-20? At least I haven't seen such a serrated part on the J-35 yet.
Do we have any verification of that rumor? I have a nagging suspicion that it was spread to counter certain hostile sentiment that SAC was a useless enterprise sitting around doing nothing innovative.
As for those particular parts, there hasn't been any clear high-resolution image of the J-35 taken from close quarters to make that judgement. However, the parts can only belong to aft fuselage, likely near the area where the body terminates and the engine nozzles begin. Anyway, the diameter looks way too small for J-20.