Austin seems to go through several wardrobe changes during his bionic demonstrations for Oscar and his associates; unlikely in the scenes taking place outdoors.
William Shatner's character, Josh Lang, is running from the military police. There is an APB radio call for him. He is described as 5'11" with blue eyes. Shatner is 5'9" with dark green eyes (leaning towards hazel). Blue eyes are translucent and pale, his dark green is much more opaque, so this is a huge difference.
About 8 minutes from the end, Steve Austin hurls himself up to climb to the scaffolding where William Shatner's hammy character is standing. The stuntman takes over Lee Majors and the long shot shows Steve Austin with his head down, looking at his feet. But the character is going up. Who does that?! Of course, the man is looking where he is going---that is to say, down---thus revealing that the footage was filmed jumping down and then was reversed.