Looking to buy accidented 325 -Headlight condensation

I'm considering the purchase of a previously insurance write-off 325i E90 model. The original owner crashed it in a tree in the center of the bumper. There was considerable front-end damage, but airbags did not deploy. They were able to repair the entire car, but decided to re-used the accidented headlights. They look fine, but some of the retaining clips are busted. Also, the headlight seal seems to be affected because there is considerable moisture in both headlight assemblies, but no cracks are visible.

The dealer claims that this is because he had just washed the car. I'm wondering how the seal on these headlight works, and are they truly 100% sealed? or is the moisture due to having too humid air in the headlight assembly?

The deal on this car is too good to pass up, but having the replace the headlights at $1k per would make the deal much less attractive. Does anybody have any info about how the seals work on the headlights and what causes the condensation inside the lens?

Moisture inside the lense isn't normally caused by the car being washed..... cars get sent to the SPA after service everyday and none of them are sitting in the lot with condensation in the lenses. Generally at the dealership if we find a headlight or sidemarker... in your case its all one assembly, we just replaced the entire unit.
I'm a tech for a dealership in massachusetts btw.

as for your other question, I just looked up online for your car with xenon headlights and I can't find any listing of any seal that would be between the lense and the housing. That doesn't mean it exists but BMW in its infinite wisdom or its manufacturer may not offer it seperately. Usually there are just tabs around the lense holding it to the housing that can be undone and you can remove the lense from the housing. You would then need to find a suitable silicone sealer and reseal the headlights. If you need instructions on how to remove the headlights or any other technical help let me know.

BTW: The 'retaining clips' are the plastic hooks thingies that are used to fasten the headlight assembly to the top of the radiator brace.