Hi,
No, I have a PicIV and there is no such thing as pal or ntsc (never the same color) on them.
those modes are for native Amiga screenmodes only. As the PicIV is actually a pass thru with flicker fixer and scan doubler it will pass whatever the machine gives it. ie: what you give it is what you get.
Of course this all has nothing to do with gfx screens. Ask Doomy.
Chris