Let's start at the very beginning.
Needing to get into the second Death Star's shield generator bunker, Han Solo leads a team to the facility's back entrance and tries to find a way in. With the door guarded by Scout Troopers, Paploo the Ewok steals one of their speeder bikes and leads a bunch of them away, leaving just a solitary guard. Han, being a master of strategies that would work in a Tom & Jerry cartoon, gets the Trooper to chase him around the corner and into a full-on ambush.
None of the members of the strike team were ever named, but continuity Polaroids taken at the time do at least reveal that the guy in the front with the prominent white beard was played by an actor identified only as "L. Burner":
Like today's review said, a 2002 publication named Burner's character "Nik Sant":
And for 13 years, that was where it ended.
But in 2015, Clone Wars' Commander Rex showed up in Rebels, and he had a new look:
Rebels Season 4, Episode 14, "A Fool's Hope," saw Hera recruiting all the allies she could. One of them was Rex, who got a new design by Eli Maffei:
Sabine's narration in the series finale of Rebels informed us "Hera fought in the battle of Endor, as did Commander Rex." Dave Filoni made it a vague reference at best, for the same reason Mando met IG-11 instead of IG-88: Filoni doesn't want to forcibly supersede the old canon unless he needs to. Declaring that Nik Sant was secretly Rex wasn't something that needed to happen, so Rebels didn't literally show us Rex standing in Nik Sant's spot... but the Galaxy of Adventures short "From Smuggler to General," sure did!
Galaxy of Adventures isn't specifically canon. But the Little Golden Book I Am a Clone Trooper is, and there he was again, looking just the same:
"Years later, Rex and other clones joined the Rebellion to fight the Empire."
So you know what that means! Hasbro could put some new forearms on this figure, possibly paint the skin a bit darker, and rerelease it as an official Rex somewhere down the line!
Then you can figure Nik Sant is the one with sleeves, and Rex is the one with armor - that way everybody wins! Especially Hasbro, who gets to sell us 95% of the same figure again.
