As you may or may not have been aware, Topps Bunt has been around for close to 3 years over 2012, 2013 and now 2014. The confusing part is that 2013 and 2012 cards DO NOT score points in 2014, and only the new cards are going to get you anywhere.
That doesnt mean the cards arent collectable or valuable, and its definitely in your best interest to consider incoming trades for the rarer cards.
The difference between 2014 and the earlier years is that base cards can go from common to super rare and all look the same. Check the back of the card in the trade to see the rarity. Additionally, the insert vs base card value spectrum still applies, so the signature cards and rare inserts are still the most valuable.
If you have any questions about trades with older cards, you can counter offer with 2014, or just one of the more experienced traders or the Topps team themselves.
Keep in mind – value for 2012 and 2013 has been drastically reduced in 2014, and its always better for newbies to try to build a playable collection before dabbling in the earlier years.