[resiz3d]

I think the costume's a misdirection. They've made a really big deal about who she might be and the secrecy of it all, Domino by herself would be too easy. Also, their suits are similar but not the same. Domino was not wearing the large belt she now uses as a sports bra. (could be stolen from someone else after the TF tho) If Domino was She-Rulk why would she attack Wolverine?

And after re-reading the issue, Domino and Elektra both realize there's a 3rd party who may be pulling the strings. Most likely She-Rulk. They go offscreen to look for her, She-Rulk beats em up, steals their weapons. (and perhaps clothing)

There's also a small chance of She-Rulk being a fusion of Domino and Elektra. They both went "offscreen" together before She-Rulk's appearance and she's carrying one of Elektra's sais along with Domino's gun. Red is Elektra's color! But I kinda doubt it.