It would probably be a mistake to consider this healing as the Sacrament of Chrismation/Confirmation, which always happens after Baptism.
Father Haydock’s Bible Commentary:
Ver. 17. Laying his hands on him. This imposition of hands, made use of on different occasions, was to pray that he might receive his sight, as well as the grace of the Holy Ghost, which God sometimes gave to persons not yet baptized, as to Cornelius. (Acts x. 44.) (Witham) — This imposition of hands, was not the same as that, by which the faithful were confirmed, or ordained ministers, but a ceremony commonly used by the apostles to restore health to the sick. If Saul, in consequence, receives the Holy Ghost, it was an extraordinary miraculous event, which was not an unfrequent circumstance in the infancy of Christianity. The Almighty, who establishes the laws of grace, can dispense with them himself whenever he pleases. (Calmet)