From what I can see in-game, both turret cheek’s materials are identical, with the same thickness and both are covered by FY-5 heavy ERA.
Somehow, the right cheek is about 100mm stronger than the left one,
this applies to both ZTZ-99A and WZ 1001.
Bug report if you consider it as a bug, Thank You:
https://community.gaijin.net/issues/p/warthunder/i/zlQoxv1U81cR