Its an extremely common practice - when the previews go out the final film's own music hasn't been written, so they have to use a different one for the trailer. I'd have said we should be honoured that the Stargate music is so powerful and dynamic that its usable for other shows.
E.g. the music for "Backdraft" was used in trailers for: Waterworld, Jurassic Park, Jurassic Park 2, Dragonheart, Hard Rain, Braveheart, The Mummy (and others);
whilst the music for "Braveheart" was used for: Titanic, Rules of Engagement, Cast Away, Enemy at the Gates, LOTR:FOTR etc.