Were AT-AT Walkers in "Star Wars: Rebels" original ones?

AT-AT Walkers are surely tough guys as seen in the movies, especially in Battle of Hoth.

In S01E01 (Droids in Distress) of Star Wars: Rebels TV series,

Were those Walkers original ones appeared in the movie or small versions?

Initially, I thought they were small versions. But, then I noticed that the weapons used on Walkers were some kind of illegal weapons capable of destroying Star Destroyers. So, it's possible that those Walkers were original ones.

Can you deduce whether they were original ones or not?