As far as I can tell, this droid has never had a name.  During the briefing scene we can see the dome just in front of Han Solo, and the body just behind Luke.  It’s not the most spectacular droid, certainly.  The dome striping is similar to R5-D4, but with a black or grey instead of red.  But between Hasbro and Disney, unmade astromechs are getting in short supply.  Many droids can be seen wandering around the hangar, but most are heavily obscured, and some appear to be reused from previous scenes.  Likewise, each pilot has a droid barely visible over their shoulders, but any that can clearly be distinguished have already been made.  This one is easily verifiable, and has not yet been attempted.