The comic got it WRONG... double wrong.
Rumble IS the red one. Always was in every source
except the G1 cartoon, which frankly... just got it wrong. New versions of G1 Rumble toys are also always red, so if you don't believe me, then believe Hasbro.
The reason this is a double screw-up is because Rumble was
already established to be the red one in IDW's continuity. So they pulled a switch for no good reason.
However, if you ARE in the oldschool G1 cartoon camp, you shouldn't be complaining about the colours... the interior art shows Rumble in his
true G1 cartoon colours:
purple & blue!
Seriously... go back and watch the cartoon. Rumble was never coloured like Frenzy. He was always lavender and blue. If you're going to give Rumble G1 cartoon colours, you should at least get them right.
zmog