Help with loose UCA nut, shock question

Two questions for anyone who's messed with the suspension on these things before. First, when doing my upper control arms I dropped the nut that goes on the end of thru bolt holding the UCA to the frame. Obviously, it got replaced. However, it is still loose somewhere in the engine bay and have driven pretty hard with no luck getting it to come out. It makes a pretty bad rattling noise any time I drive over a bump and is driving me nuts. Any ideas on where it might be/ how to get it out? Have tried using a long magnet and taking some pictures w/ flash but no dice.

My second question is, when I did my front shocks (King 2.5s) I added 5 turns of preload to get the ride height level with the rear. The rep from King said up to 6 turns is fine, you can go up to 8 if absolutely necessary but I was happy with the height adding 5 turns. There's about 2/3-3/4 of the threads above the adjuster and 1/3-1/4 below. I do notice that they top out pretty hard on on rough sections offroad, i.e. if my wheel slips into a deep rut or something. Is this normal or will the shock not perform well/ end up with damage? If I do take a turn or two out would I need to get an alignment done again?

Thanks in advance, I'm trying to iron out a few issues that came up after building this thing.

 

I should add- regarding the upper control arm, it dropped off the rear part of the bolt as in the side closer to the back of the truck. The only parts I could see where it would have dropped are near the front motor mount, frame crossmember, or by the transfer case. There's a few holes on the side of the frame rail but none look big enough to allow the nut to fall in. Everything else has been retorqued and this noise just started after swapping the shocks. Swap bar has been removed as that was contributing to the rattling noise.