Value of anything depends on who is selling and who is buying; since you can get new fenders for around $650 (each), assuming yours are not damaged they are worth at least that. Now before someone screams and say "but they are original Mopar parts", I am not saying that they are not worth more, I am just saying they are not worth less (unless there are issues). Point in case, if you found someone restoring a 70 6 pack or hemi car that desperately wanted/needed original metal, well then they might be worth $1000+ or more, but who knows. I generally price things as I feel they are worth, sometimes I am high, sometimes I am low but so long as I do not sell something and then regret it, its all good. When it comes to these cars, everyone wants to think they have a gold mine that will somehow yield big money, and some people do, but overall there is a median price there somewhere that is not astronomical now it is bargain basement. Since they have been installed, painted and been on a car for some time, they are not new or NOS, they are good used fenders. Since they are factory, if they were mine I would probably start at something like $750/each and throw "OBO" on there. So long as they pay for your new fenders, you are probably doing good.
As to the headlight buckets, there really isn't any adjustment, they screw generally into plastic inserts that are in the fender lips as I recall. Look you really don't know what you don't know, until you take it apart and really see what is going on you won't know. It is possible that something is not bolted up correctly (don't know what they could be but...), I have had many things car related "just not work" or work the way I wanted and then after fiddling with it for awhile all a sudden it does; cannot say way this happens most of the time but it does.