510.1 Unpublished Works vs. Published Works
If the U.S. Copyright Office issued a registration for an unpublished work and if that work was published sometime thereafter, the Office will accept another application to register the first published edition of the work (even if the unpublished version and the published version are substantially the same). 17 U.S.C. § 408 (E); 37 C.F.R. § 202.3 (B) (11) (I).
When completing the application for the first published edition, the applicant should provide the registration number of the unpublished version using the procedure described in Chapter 600, Section 621.8 (F). If the application for the first published edition is approved, the registration for that edition will exist alongside the registration for the unpublished version.