Yes. If a service body does not have bylaws, it must have a summary/statement of purpose and operating procedures. Both choices must conform with OA Inc. Bylaws, Subpart B, that they must say their purpose is to aid with the problem of compulsive overeating using the Twelve Steps and Twelve Traditions, and that they are guided by the Twelve Concepts of OA Service.
Source: OA Inc. Bylaws, Subpart B, Article VI, Section 2a) 2