OCS/ECS scandoublers/flickerfixers will work in an A4000, but they don`t support the full colorrange of AGA as they are only 12 bit (4096 colors) especiallly HAM8 pictures will look funny through those scandoublers.
You can identify them easyly by the "short" videoslot connector.
By the way the majority of the scandoublers that go into the videoslot are non AGA. The only I can think of, beside the Arxon we are just talking about, is the scandoubler module for the CV64/3D and one from Micronik.
