That's a Lowery Organ rather than a Hammond. If they are at Abbey Road then that will be the organ that Billy Preston used on Let It Be with the Beatles. I should point out that I'm a Pink Floyd and Hammond fan, but not a Beatles fan.
Pink Floyd's long an varied history is captured and documented here in a series of thousands of photographs contributed by Pink Floyd fans around the world. Pink Floyd are well documented throughout all of their career in this gallery although you can never have enough Pink Floyd. As such, if you have any Pink Floyd materials to add here, please do get in touch as it is great to share all these amazing images with other fans. Pink Floyd concert images from the early days are of particular interest. Long live Pink Floyd! ;-)