You need to have reached max prestige on MW3 in order to get the new backgrounds.
These 4 are only unlocked if you’ve reached max prestige in MW3 (max prestige in MW3 is counted as 10th prestige according to ATVI) and/or Black Ops 2. There are two more that you get for just playing Black Ops 2 or MW3!
As crazycanuk stated. These backgrounds are obtained from performing certain feats with the previous titles. For more information on this please check out:
Also, please try to play some matches from MW3/BO2 and see if the backgrounds push to your account.