Trivia: Scotty visits the bridge from "his" Enterprise (from the original 1966 Star Trek series) on the Holodeck. As the original set had long since been destroyed, the captain's chair and center console used in the episode was donated by a fan who had recreated a life size version of the bridge. The turbolift alcove and one of the stations was built on-set (and re-used in the DS9 episode "Trials and Tribbleations"). Everything else was made up of footage from the original series that was looped.
Trivia: In the Holodeck, you see Scotty's right hand open on the glass and later on the bottle. It can be seen that his middle finger is missing. James Doohan kept his hand closed most of the time on screen because he lost it in World War II.
Chosen answer: The uniform does indeed change colour. It may be due to the need for a green screen in part, or perhaps some lighting altering our perception. That being said, it certainly looks green at the start, blue thereafter.
The show has been done in HD now and not sure if they fix this problem.
Dan23