I reread a newspaper clipping from my father's hometown newspaper dated August 19, 1944. At that time he had finished aviation mech school in Great Lakes and finished Arial Gunners school at Jacksonville. The article stopped there, but he spent the next year assigned to a squadron that spent time at Corpus Cristi and San Francisco. Squadron had deployment orders for Okinawa for Mid-August '45 when the bomb dropped.
Can't say that they would have been involved in that first wave, but it sounds like they would have been right there. Sounds like my father might have been riding one of the fifty calibers. (I imagine the barrels get a little hot!)
Did your father see action?