To those of you who though saw MK2 on the PS store, you are not crazy it seriously was pulled off the store.

Mortal Kombat 2 was a classic game back in the day and the sales for MKII shows it. It was one of the best sellers on PS store until it was pulled off with the latest firmware update 2.5

"A Mortal Kombat II specification is being upgraded in connection with the release of the latest firmware update," the company told 1up. "This is one of our top titles on PlayStation Network, we are working diligently to get this back up." 

Sony did not talk about the games that were already downloaded onto peoples PS3 but chances are those games will get updated as well when MKII is re-released.

Source