8 CFR §328.4

1. (a)Application. An applicant for naturalization under section 328 of the Act must submit an application on the form prescribed by USCIS in accordance with the form instructions and as provided in 8 CFR 316.4.
2. (b)Evidence. The applicant's eligibility for naturalization under 8 CFR 328.2(a) or (b) will be established only by the certification of honorable service by the executive department under which the applicant served or is serving.