Acts 2 happened AFTER Jesus gave the Great Commission, yet they were filled with the Holy Spirit before any of them were baptized. At least before any of them were reported to be baptized. There were many other records of people accepting Jesus, being filled with the HS and then being baptized. All I am saying is that baptism is NOT necessary for salvation. (Boy, is THAT going to cause dissention ) :>)
Only if you take the biblical arrangement of books as chronologically 'real.' the Gospels were written after the Acts was written. The Gospels were written after the Epistles too. Which goes to show you why there is disconnect such as people receiving the HS according to Acts and contrary to the Great Commission which was written, apparently unaware of the Acts, a decade or so later.