If it is neatly done, you can just leave the cut edges bright, I've got one like that and it doesn't look bad. Otherwise, touchup with a good cold blue is what most gunsmiths do. Along the cut edges there the small difference in color should not be obvious and it is not a high wear area.
Either would leave you with the unmodified bulk of the slide in its original finsh.
Either would leave you with the unmodified bulk of the slide in its original finsh.
