Viper, as far as I know, the Aniversay can be acquired by one of two ways: either a boxed retail version, or a downloadble one. Althought, to go for the 2nd option one must have Legends. So the 1K/1.25K rule isn't disregarded.
slightly off-topic: why some ppl just looking for "easy achievements". The challenginf ones are the better, and by all means much more respected. Anyway, I also hate the "be #1 in the world leaderboard" kinda achievement.