Don't complete it until the DLC releases!!
Planet Destiny confirmed that when you turn in an exotic bounty after the release you will receive the version 2.0 of that weapon!!
You won't need to waste your shards to upgrade it!
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Got Invective and Super Good Advice the other day and I did wonder about turning them in after the DLC drops but I wasn't doing the bounties to use the weapons I wanted the Exotic Shards. Dismantled.