Yes, indeed every one who believed in Christ and accepted him as his follower they are already been baptised with Holy Spirit (indwelling) which is an inward state of Baptism which is an act of immersion one self in Christ by dying of carnal life and walking in Spiritual life with Christ with the hope of Spiritual resurrection with Him. Where water Baptisim is an act of outward appearance of inward work of Holy Spirit in believers. ‘As the word Baptisim comes from greek work Baptisima and this is the common word used to both water and Spirit Baptisim.’ I Believe a person can be baptised with Holy Spirit even before undergoing water baptisim.
I was baptised with Holy Spirit when I accepted Christ as my God and saviour and believed scripture without doubt even though I was not yet baptised with water. And couple of months later I made public demonstration of my beliefs by water baptisim. I believed as I was lead in the works by Holy Spirit by its guidance in understanding Scripture and resisting to commit Sin against God. Even though I was new convert in faith I had strong convection of what I believe and by today it had built up without any doubt and fear.