Looks like a Model 1917 from the DA 45 stamp but the lower front of the frame has a "Made in USA" stamp that didn't come along until 1922. It is possible the barrel and cylinder were replaced on a later 2nd Model N frame. I don't see a Brazilian crest on the sideplate. I wonder if the top of the frame is flat or rounded. If there is a small trademark stamp on the left side, it is a commercial version.