I am not entirely sure but given the fact the Dataflyer 500 and Dataflyer 2000 are identical boards and the A1000 uses the same type of interface with nothing more than a reverse zorro interface I would find it hard to believe that Expansion Systems would have made another type of board.
Look inside the Dataflyer 1000 and see if the zorro board inside is connected to a small adapter. The A500 uses an extender adapter so it would not surprise me if the Dataflyer 1000 uses an adapter that reverses the pin order to be compatible. I would venture to guess that the Dataflyer 500/2000 and possibly the 1000 are the same board with different housings and adapters. I am using my Dataflyer 500 in my A4000.
Good luck