Are we certain ? Edit
All we know with certainty is that three Trill scientists came to DS9 aboard this vessel. We have seen similar vessels used by Bajorans. For example, Razka Karn had one in the Badlands in the previous episode Indiscretion. Isn't it possible that the Trills booked passage to Bajor, then chartered that vessel to take them to the station ? It was never specifically referenced as a Trill vessel in the episode.