I disagree. The plate has no contact with the carb - there’s a gasket on top of it - so conductive heat from the plate isn’t an issue. And even if the plate gets hot, it can still direct hotter air around the carb.
That said, I don’t the think the plate acting as a heat shield will have any significant affect. But it was fun and is pretty interesting under the hood.
I do think that doubling up the base gasket and sandwiching the plate in between will insulate the carb from engine heat better than one gasket though.
Maybe I’m wrong. If I am, it’ll take 4 minutes to undo. Regardless, I’m having fun with it.