Go the to blueprints machines in the tower (where Zavala, Ikora Ray, Cayde-6) are. From there you can see what is carrying over and what isn't.
For example, Gjallahorn and Dragon's Breath didn't make it to year 2, so I dismantled 2 of my Gjallys. Khepri's Sting for my hunter didn't make it so I dismantled it but my Akhamkara gauntlets will make it to year 2 so I kept it and when I get enough legendary marks I'm gonna buy the Year 2 version of em (boosts to 280 defense and higher discipline or something)