37 CFR § 2.200 - Assignment records open to public inspection.
(1) Separate assignment records are maintained in the Office for patents and trademarks. The assignment records relating to trademark applications and registrations (for assignments recorded on or after January 1, 1955) are open to public inspection at the Office, and copies of those assignment records may be obtained upon request and payment of the fee set forth in § 2.6 of this chapter.
(2) All records of trademark assignments recorded before January 1, 1955, are maintained by the National Archives and Records Administration (NARA). The records are open to public inspection. Certified and uncertified copies of those assignment records are provided by NARA upon request and payment of the fees required by NARA.
(b) An order for a copy of an assignment or other document should identify the reel and frame number where the assignment or document is recorded.