Sorry, bad use of a pronoun. By "it" I was referring to the Holy Spirit coming to the person in power (i.e. demonstrating His gifts), not salvation. To return to the example of Philip, those who believed from his testimony were saved then (if any died before the Apostles came, they're in heaven now), but they did not receive their gifts of the Spirit until the Apostles laid hands on them.
I agree that those who believed what Philip was preaching were saved. In Acts 8,you find this verse:
12 But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women.
As you can see, they were baptized. Baptism is for the remission of sins(Acts 2:38), and since it has yet to be proven that remission (or forgiveness) of sins is not necessary to be saved, I feel this only supports what I have been saying all along.