One could always rig a clear LED set up behind the blue dot lens. Not impossible.
There's a couple of problems with doing that. While it would work in theory, leds work best when the lens color is the same as the led color, or a clear lens. Using a white led, even with a red lens, you would end up losing most of the brightness as the lens would only allow the red part of the spectrum through.
A better way to do it would be to either block off the dot, so it's merely for looks (still blocking the light, though). Alternatively, one could segregate the dot within the housing, using a tube or shield, then place a blue led behind the dot. That will allow the dot to work as intended. The rest of the leds, which should be red, will need to be arranged so that they are not blocked by the dot. This is how I have mine setup, it works very well.
