WL 7.0 SP4 supercedes the SP1 and SP2. So
you should go with the hightest version available. Here's something from BEA official documentation:
Support for WebLogic Platform Service Pack 4 . . .
WebLogic Platform 7.0 Service Pack 4 (SP4) includes maintenance of WebLogic Platform 7.0, WebLogic Platform 7.0 SP1, and WebLogic Platform 7.0 SP2, as well as support for New platform configurations - Interoperability between SP1, SP2, and SP4 of WebLogic Platform 7.0... Just a suggestion try 8.1 its latest !