The regional NARA office that covers both LA and AR is: NARA Southwest Region 501 W. Felix St PO Box 6216 Fort Worth, TX 76115 817-334-5525 You can call or write them to ask if they have the naturalization for your ancestor. They then check their card file and let you know if they have it or if they don't, they'll usually refer you to which office they think may have it. If they do have it, you can order a copy from them.