Yes that is a Twiggy drive. There are many such pictures in Apples early promotional literature that got an early start, remember the Sony 3.5" drive replaced the Twiggy very late in the process.
Any developer whom Apple gave a Mac to, such as Microsoft, would have had one with a Twiggy drive.These can be seen in numerous YouTube videos in early interviews with developers from the films used by Apple to promote the Mac and at the Shareholders meeting where the Mac was introduced. So unless they were contractually bound to return the protos to Apple who destroyed them, then there should be a few left in the wild, but none have ever surfaced, much less the clear plastic protos of the various stages leading up to the final Macintosh.
There is a story that in the early days of Apple, the storage room where all the design models and prototypes were being kept to that date had been thrown out overnight by a cleaning crew thinking it was garbage, thus eliminating much of Apples early product development and design history.
