The B5 costumers actually had to make two suits because the first one went missing from Western Costume. They needed two suits because the incident being portrayed from an earlier episode, where it was just Sinclair in the scene, was being retold to include Sheridan.
So, the first suit was used by Sinclair years before the scene was shot with the two of them-- and went missing in the interim. The two new replacement suits had to match the suit that was used in the original scene, which was a huge headache for the wardrobe department. I'm not sure where they got the helmets for the newer scene.
As for the Lunar version of the suit, it does not have the arm panel (like Bowman has on his suit) and there is a cap, much like that used with the Apollo moon suit, being worn in addition to the headphones.
Scott