I've just checked my two and only the central LED is on when on constant. But it makes no difference - the central LED is so much brighter that you would barely notice the two sides ones anyway. The two side ones are there just to provide a pretty effect when in flashing mode (and so that there's something there when the main LED is momentarily off).
This^^^^
I have some of those, and some of the vertical style. There are at least two different flash patterns on the vertical ones, my guess is change of model year...
I don't see that it makes any odds either way.
In fact so little difference that I CBA to go to the garage to see if the side LEDs are lit on mine when steady or not.
They all get a quick smear of grease on receipt and I've never had a water ingress problem.
Had on drop off saddlebag loop and scatter it's parts over the road, but found to be still working when re-assembled.