Hi Michael. Yes, guides need to be black for all the ARC powerbases. For cars that come with non-black guides (including the red Carrera 'shallow' guide), I've has some luck with a high-quality black permanent marker pen, but that does wear off.
A long-term solution is using a black guide. BRM produce a black shallow blade for Carrera cars (part number S-126) which I've found available in the UK, the rest of Europe and North America. I have used them on Carrera cars and they work well. For other brands with non-black guides (eg NSR, Scaleauto), I'd suggest using Slot.it guides such as the CH10 Universal Screw Guide.
I hope that helps.