I'm confused! How could it not?
Here are the "Add Panel" items to replace the original ones:
Those are the Apps on the default bottom panel!
Also, very important, once you've recreated your Panel Layout, you need to save that as a "Named Layout" with a unique name of your choosing, using the MATE Tweak panel that Ricardo already mentioned. Below is what I saved mine as:
That way, you can always restore the named layout if something goes wrong during your GUI interactions. 