Indeed, Usually you could see it on their "gloves" wich usually soften the blow to your hands and somewhat to your oponent, however in the movie they used rope with knots tied to them for that little "extra" feeling
Also the other and perhaps MOST noteworthy is his stance... Usually modern Muay-Thai have a light and quick footwork kinda like Kickboxing, this to make dodging more easier I belive. Almost like Tochiros footwork in the movie (the poor Japanese with the afro that got his ass beaten in Ong-Bak)

While Tony Jaa firmy plants his feet in the ground, no footwork whatsoever.
If I am to make conclutions it's that ancient Muay-Thai... well you fought to kill in battles, not a competition. So you fought outdoors.... in the jungle.... no one at that time had a good pair of sneekers :happy: so footwork wasn't really needed, or very usefull.
And the last thing, the knock-out moves Tony Jaa performs in the movie are moves you learn in Muay-Thai.... but are banned to use it in the ring. Well most competitions ban them... Like our European Muay-Thai competition where they even ban the elbow. And the "deathblow" Tony Jaa deals to the Burmese fighter in the movie (I forgot the name of the move, my Thai is a little rusty) where you "climb" up on your oponent and strike the botom of your elbow right down on your oponents skull.
*phew* that was a little longer than I expected.