It's certainly possible that Swift only caught the combined glow of the western two galaxies (unresolved), but I doubt he would have resolved the eastern galaxy as a star. Swift observed at only 132x, using a custom made wide-field eyepiece with a field of 33' (implying an apparent field of ~70°). The three galaxies would be too tight to resolve at that power and almost certainly the eastern one would be too faint to see individually.

When he described a "nebula" (galaxy) as "between 2 stars", the separations of the stars could easily be 15' apart, so there's really no telling which ones he had in mind.

Steve