Panel tabs are usually just at the front, they hold the panel lower down for horses with wide withers.
There is also girthing tabs, which can be at the front and back. The front one is by the tree points and the back is near the back of the flap, they are for stitching extra girth straps to. The saddle probably has the tabs but not the straps but you can get straps sewn on if the horse needs them.
