As I understand, the new transfer features some things that were not in the original theatrical Version? In this case it may be under copyright law.
http://www.copylaw.com/new_articles/PublicDomain.html:
Whenever you rely on the PD status of a work, it is important to make sure that the particular version you want to use is actually in the public domain.
Later versions or adaptations (e.g., translations, revisions, annotated and illustrated editions) of PD works may be protected by a separate copyright.
That’s what they did for Beneath the 12 Mile Reef, the restored release is an extended cut, and of course they’ve yet to bother restoring the original.