User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-184612-20150209185907/@comment-4452412-20150209202120

Looks like if you buy 4U on the eShop you get the themes for free.

http://www.nintendolife.com/news/2015/02/new_3ds_home_themes_confirmed_for_majoras_mask_3d_monster_hunter_4_ultimate_and_ace_combat_assault_horizon_legacyplus