I'm watching _Prehistoric Monsters Revealed_ and the artist reconstructing _Ther[i]zinosaurus_ [...] says that it is believed that because there are no teeth in the front that paleontologists believe _Ther[i]zinosaur[u[s_ had a beak. Could _Ther[i]zinosaur[u]s_ have had a pad inside the mouth like camels and llamas do?
In principle, yes, but the skull of *Therizinosaurus* is unknown, and *Erlikosaurus* had an ordinary beak like *Iguanodon*. That's not what artiodactyl skulls look like.