I went a slightly different route with mine.
Mine didn't come with those O rings, though I knew they were supposed to be supplied.
I decided to glue my LED board into the lense itself.
When I say glued, I actually used a few small dots of windscreen silicone I had laying about.
This has the advantage of making the connections less troublesome to get at (just remove the lense) and if I do need to remove the LED board for some strange reason, the silicone dots will let go as I need them to.
This also made it easy for me to attach a small LED strip to the under side of the lense for the number plate light.. I have ended up with an all in one unit that can be removed by undoing two screws and unplugging one connector.
If I could get away with having the "integrated" LED board, that would have been sweet.
As it is, Ozzy law requires that our indicators be in a seperate space to any other lighting. Basically, they have to be seperate lights even if they reside within the same assembly.
My (almost) finished product! Sorry, not a great pic.. but you get the idea!