The images you posted are good, but the ZTZ99 has a very different hull that the ZTZ99A or ZTZ99B models;
Another image from the same set you provided shows the large gaps on either side of roadwheels 3 and 4, and the rear of the hull that is very different that a ZTZ 99A or B with the rear hull on the ZTZ99A-series being flat and almost 90° perpendicular to the ground while the older ZTZ99 plain jane hull is slanted at an angle:
View attachment 174671
I can't even get the a certain Army School to change the Vehicle ID charts for the ZTZ99A from the ZTZ99....
So to ensure features that ensure correct identification is crucial are important.
Or I guess I am being a stick in the mud for vehicle ID