No, they aren't.If I use a power tool to remove gaskets on aluminum, it's red roloc pads. Even still, you have to be careful. The brown roloc pads are okay on cast iron or steel.
The brown pads were what was being used in the Chevy dealership I was at in '84. The guys called 'em "cookies" as they looked like big Ginger Snaps. My machinist at that time told me castings were coming into the shop with the gasket surfaces wavy--aluminum worst, but even some iron castings were being worn.
And as said, the abrasive dust goes everywhere.