The discussion in this string has been about Confederate soldiers who gave themselves up, or were captured, and willingly took an Oath of Allegiance to the U. S. government during the war while Confederate armies were still in the field. Their alternative was to go to a POW camp and hope for a release on parole. Only those soldiers who were being held in prisoner of war camps when the war was ending were faced with the issue of taking an Oath of Allegiance in order to gain their personal release.
Soldiers at their post when surrendered, and absentees at home who later reported into Federal parole centers or local provost marshals to be accounted for, were released on parole. The language can vary, but this end of war parole was primarily a promise to not take up arms against the United States until properly exchanged. The technical possibilty of exchange evaporated when the Trans-Mississippi Department was surrendered at the end of May 1865.
Your soldier would have missed out on receiving a parole under the surrender agreement at Greensboro, North Carolina by going home the night before the surrender. Many men quit and headed home from North Carolina when the negotiations were known to be underway. However, as an absentee not accounted for and paroled with his unit or detachment, these men would have been expected to report into a Federal provost marshal in a community nearest their home to be accounted for and paroled. These absentee paroles given and received after the end of the war ended up in their Compiled Military Service Records.
Your soldier could have made it home without ever giving his parole although once home, and understanding the requirement, it was rather foolish not to go to the nearest Federal provost marshal and comply. Some of my 12th Louisiana soldiers who were paroled in their camp with the regiment near Greensboro apparently did not hang onto their parole certificates. Unable to produce them when asked by a Federal provost marshal encountered en route home, they had to swear to a second parole before being allowed to proceed.
Once home, the issue of taking the Amnesty Oath which restored or granted one citizenship would have come up in conjunction with voter registration, recording changes in property ownership, running for office, paying the taxes on Tara, etc. I will let the Alabama experts address your question of where you might find a register of these amnesty oaths. These are state matters and the rules and requirements varied from state to state. Amnesty Oaths taken after the ex-soldiers were at home did not appear in the Compiled Military Service Records that I have examined. The Amnesty Oath has to do with accepting the Union victory and specifically the abolition of slavery.
My great grandfather was paroled at Greensboro with the 12th Louisiana Infantry and returned home to Louisiana. He was not among the 14 classes of Confederates who had to apply for a Presidential Pardon. He therefore could have gone to a local Federal provost marshal at home in Louisiana and taken the Amnesty Oath, but I have found no record that he ever did. However, I do have his voter registration papers which he saved from 1867 when Congressional (aka Radical) Reconstruction supplanted Presidential Reconstruction in the spring of 1867. The voter registration oath he took was not exactly the Johnson Amnesty Oath. He had not been registered to vote prior to the war, nor held any office requiring that he swear to support the Constitution of the United States prior to the war, and therefore was not proscribed from registering simply because he had voluntarily participated in the rebellion as a Confederate private soldier. And President Johnson issued a sweeping general amnesty for all ex-Confederate in December 1868 just as he was leaving office.
The circumstances for taking the Amnesty Oath can be very confusing. I hope this helps!