Upon receipt of a proposal requesting Class III gaming procedures, the Secretary must:

(a) Within 15 days, notify the Indian tribe in writing that the proposal has been received, and whether any information required under § 291.4 is missing;

(b) Within 30 days of receiving a complete proposal, notify the Indian tribe in writing whether the Indian tribe meets the eligibility requirements in § 291.3. The Secretary's eligibility determination is final for the Department.