You're welcome Donna.
Don't know how to help you but if he was naturalized citizen than there should be an intent & petition, someplace. Yes, at least you know when he was born etc. but having the surname he came to America with would be a frosting on the cake. How many more different spelling of this surname have you found? Please list them maybe we can come up with something. I take it the surname on his tombstone is GNADZINSKI?