Like the Hammerhead Corvettes and the Ghost, the CGI model for the Dornean Gunship in Rogue One originated with the Star Wars Rebels production team, not with Rogue One’s ILM team.
Star Wars Rebels season 3 continues Saturday, January 21st, with “Trials of the Darksaber” @8:30pm on Disney XD.
For all the ships from the animated series that show up in the film, the Rebels team provided the digital models to ILM, who remodeled the ships to look believable in the live-action setting.
The Dornean Gunship was originally labeled simply as “ROJ BG Ship,” either standing for Return of the Jedi Background Ship or Return of the Jedi Bill George Ship, after the ILM model maker that designed it.