I believe IW have already confirmed this (as long as its within the same console family ie PS3/PS4 or X360/X1),
I know if you buy it on PS3/360 it will transfer over when you upgrade to X1/PS4 however im not sure if it works the same going backwards... ie you enter your SP code on your PS4 system and then go back and download the maps on your PS3 (not sure if ive explained that very well)
During its Call of Duty live stream today, Infinity Ward announced that players will be able to transfer their Call of Duty: Ghosts stats across platforms -- including from current to next-gen systems.
By logging into their Call of Duty Account (which already exists for Call of Duty Elite members or can be created for free), players will be able to download their profile to access their stats from any console.
As described by Activision, players can "carry their profile wherever they go, from console to console, current gen to next gen, second screen and more. So when players are ready to move to next gen systems Xbox One or PlayStation 4, all their Call of Duty: Ghosts stats, in-game achievements, unlocks, and more will seamlessly go with them and be ready and waiting."