I don't have a 2000 handy that has the variations you're talking about but my guess would be that it wouldn't be able to display both since Denise is the main video processor and Agnus controls chipset operation and ram access.
My assumption would be that Denise has to have NTSC/PAL capability for a system to be able to display it but it's only my assumption.
I wouldn't assume because WinUAE demonstrates an effect that it would be the case in real hardware. The screens are subject to so much software on a UAE system it wouldn't be clear to me that this was because of chipset code.
just my two cents.
