Cannot stress this enough. There are times where you will be asked to dismantle items in quests/ Gunsmith Tasks. Keep your old weapons for this as they count. Example would be ' Ace of Spades' exotic hand cannon that you get as a Hunter when you hit gunsmith Rank 3. Part of the quest is to dismantle legendary hand cannons. I don't have this gun yet because I haven't started on my hunter yet but by all accounts it is like the fate bringer on steroids so I will definitely be working towards that one! Year 1 weapons count for this. I had to dismantle legendary or rare shotguns for my Titan rank 2 at Gunsmith. This gave me Immobius - Awesome Shotty!