DON'T dismantle those rare and legendary weapons just yet because......
The gunsmith needs you to dismantle weapons for his quests that we have coming. So hold on to what you have space to keep. Shouldn't be too hard with 72 spaces in the vault now. Link below. There are other quests listed in destiny tracker as well.
May the force / light be with you always
Lando_75
http://db.destinytracker.com/quests/2507548598-back-in-the-saddle
Edit:
Here is a link for the gunsmith quest to get the 1st curse
http://db.destinytracker.com/quests/677711641-imprecation