Just started, having a blast exploring the first harbor area and finding all the hidden chests, however I just realized should I be saving these for later?

The loot seems to be randomized based on my level, all I'm getting are common items even from the purple chests. Should I not be opening these yet? I also read that unique items won't drop in the world until you buy your first unique (what an odd mechanic) does this also apply to fine items?

Also is there a way to sell items from your camp or do you have to haul them all over? Should I be selling or dismantling them? Do dismantled weapons give weapon upgrades?