You may be thinking of the poster. Compare the statue to this and this.
How can you possibly tell how armor-like his pants are? It's a rectangle either way!
I'm-- I'm very stuck on that point.
There's also no sleeves on Roy's armor.
Additionally, these kind of statues are intended to show the person in question in a heroic pose. Beheading a random civilian in civilian clothes rather goes against that -- logic would dictate the person he's conquering would be an enemy, in armor. I'm not sure why the rectangles do not look armor-y enough.
The only two things that are different are his lack of the right boots and the shoulderpads. The belt is quite a bit higher, though, now that I look at it, so that's another thing.
Again, though, not supporting that that was in any way intended to actually be Roy on that statue.