Does it really matter what type bulb?
Incandescent bulbs are as waterproof as they can make them. Have to be, soon as air gets to the filament it's gone.
Don't know if it really helps but it makes me feel better about it disconnecting the trailer lights before backing into the water. I don't re-connect until I've got the tackle &c loaded back in the truck and I'm ready to hit the road.
I've read that LEDs are a lot hotter than incandescents. Will that cause a prolem with the plastic lens, maybe melting or burning them?
If you know how many firearms you have without stopping to count...
...You don't have enough guns.
If the dollar value of your firearms exceeds the value of your ammunition...
...You don't have enough ammunition.