Did the labels have certified copies of their copyright registrations?
They will typically also handle copyright registration and "ownership" matters for the composer.
Shown below are fees for copyright registration, recordation, and other services.
All information you provide on your copyright registration will be available to the public and some of it on the Internet.
Requests and applications for copyright registration are found in the record books.
Pre-publication, production and post-publication services (such as copyright registration) are also available.
Adobe Systems has received the first copyright registration for a computer program that generates a style of type.
In addition, the website also provides a means of searching copyright registrations and recorded documents from 1978 forward.
What is the difference between mandatory deposit and copyright registration?
This list, taken from advertisements and copyright registrations, is not verified as being complete, nor are all works known to have been produced.