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If you are asking this question then I would recommend you get a competent gunsmith to do it. 1911 parts require fitting. Some a little, some a lot. There is no way I can know your skill level as it pertains to pistol work.
I have a STI trigger in my Sig 1911 XO. It required a "bit" of filing on all 4 sides of the trigger (and polishing/finishing...) to fit properly.