Seagate and Western Digital don’t have any SATA2 drives. All of their drives are referred to as SATA 3gb/s. CDW carries quite a few that they call SATA300 drives, only one that they incorrectly refer to as SATA2. A few controllers are called SATA2 or SATA II probably in error. Here is an explanation from Wikipedia:
SATA II misnomer
Popular usage may refer to the 3.0 Gbit/s specification as “Serial ATA II” (“SATA II” or “SATA2”), contrary to the wishes of the Serial ATA International Organization (SATA-IO) which defines the standard. SATA II was originally the name of a committee defining updated SATA standards, of which the 3 Gbit/s standard was just one. However since it was among the most prominent features defined by the former SATA II committee, the name SATA II became synonymous with the 3 Gbit/s standard, so the group has since changed names to the Serial ATA International Organization, or SATA-IO, to avoid further confusion.