If you're unsure what box model you have, go through the following steps:
Open the Menu
Select Settings*
From Information & Reset select Device Information
If you're not able to get into settings, you will be able to find the box model printed on the back or on a sticker on the bottom of the box.
*Settings can be found via the cog in the top right corner of the Menu. You can get to the cog by pressing Up and right after opening the Menu.