unlocking items from drops

Ok, I found a purple flatbow last night, and I read here that some items unlock other items (used for upgrading?). But I also read here that if I wanted to scavange it an expert salvage kit would be the best way to go. Well I'm poor so I only had a regualr salvage kit. However when I salvaged it it unlocked a bow grip and a string.(I've forgotten the actual names but it isnt important). My question is are these items that were unlocked, are they used for upgrading or what. I have the basics on salvaging items, but I do not know anything about runes or unlocked items.

thx

They are unlocked so then you can use them in PvP, you have to use an expert kit to get the upgrade componenets, and then it is only a chance to get them.