Question in regard to doing AF quests all over again since 1.0

Hi guys, I originally did all my class quests back in 1.0, but just recently returned to FF14 and had to do them all over again since things had changed. This wasn't an issue with the LV45 quest that gives four pieces of AF gear... however the same cannot be said for the LV50 quest for the chest piece.

Since I technically did the quest forever ago, I already have the chest, but I can't complete the quest BECAUSE I have it, even though I didn't run into this issue with the LV45 class quest on PLD or BRD.

I'm paranoid about tossing such things out of my inventory though, so figured I'd poke my head in here, and see if anyone has experience with this issue?

I don't remember having an issue at the time. Some people complained because they finished the quest with the chest piece on a retainer. As such, the game couldn't check they already had it and gave a second chest piece (they were not tossable at release).
I suggest you toss the piece, complete the quest and get a new shiny chest piece or finish the quest with chest piece equipped

I believe also if tossed the Calamity Salvager would have it in his purchasable wares. I don't think you would be loosing out on anything if you tossed it, since the quest you are attempting to complete will reward it.

You can probably complete it if you just tossed the gear on your retainer or the amoirewhatever storage thing in the inn