Yes, it means Special Pokemon.
>Pokémon SP (an abbreviated form of Special Pokémon) vary depending on the theme of the expansion in which they appear. All Pokémon SP are Basic Pokémon and have a stylized "SP" logo in the bottom-left corner of the illustration box. Pokémon SP also include a suffix in the name in order to differentiate them from other Pokémon.
Source: Bulbapedia
