RED LED is red in the pure light spectrum... so it is red. Blue LED is the same... blue in the light spectrum. WHITE LED is VERY expensive, so 99% of white is a blue LED with a phosphour coating and something like Galium used to excite the phosphours. As such depending on the manufaturer, white LED will be varying shades of blue through to a yellowing white. Colour white is also dependant on the batch made... one batch cannot be guaranteed to match another etc.
How they will affect the machine is really dependant on the inserts used and the true colours in them. If you have a true blue insert and place a RED led behind it... you will see next to no light come through as the light given off by the LED will only be picked up by any red in the insert.
I put some LED's into my CENTAUR... results were very disappointing.... absolutely no difference on the orange/ red to a standard 555 globe. Green was a little better. Blue was deeper but also duller, plus there was a lot of strobing. I kept some and went back to standard 555 on the orange inserts
