Lemme explain.
Most professional writers, ca. <1976, did not file for copyright; their publishers did, as they were (typically, by that time) under contract to the publishers. Performers were often more concerned with recording songs than the esoteric detail of the copyright & publishing business.
The writers (the Eagles) like many rock artists, typically did their arrangements “by head” or in the studio. They may not have had anything written down, and many rock musicians read music little, if at all. Between the concept of an Eagles’ song and the final recording, there may not have been any written music. (exception: sweetening tracks)
So by the time of the final album release, it’s entirely possible that no written music existed of the songs other than a scratch chord chart. Not only was that possible, it was common, which gave me an occupation – writing down what was only, until then, a sound. I made a pretty decent living filling that gap.
The applicable copyright law was from 1909. In 1909, audio recordings, although they existed, were not a serious medium. If you had written a new song <1909, your medium for reproduction was the printed “piano/vocal” sound sheet. Millions were sold. Sound recordings, not so much. Logically, when the law was codified, a written copy (“the best copy”) of your composition was required for deposit in the US Government Copyright Office.
If you, in 1909, could write music, you filed that with the CO. If not, you hired someone to write down what you played on your instrument in some readable form.
A lead (pronounced “leed”) sheet, for those who are not familiar with the term, is defined as follows (my definition). It contains, in written form, the following:
[ol][li]The melody, if any, in standard musical notation, [/li][li]The** harmony**, if any, usually expressed in chordal symbols,[/li][li]The lyrics, if any.[/ol][/li]
A lead sheet (theoretically) is sufficient for a professional musician to recreate the original composition. Obviously, given the 60+ years that had elapsed since the 1909 law, there was much to be desired. Nevertheless, a lead sheet was a useful tool for many purposes, including the arranger of the sweetening charts.
The US copyright office accepted lead sheets for song copyrights for a very long time, so long that Hollywood publishers came to use lead sheets for the de facto copyright medium. I made an occupation of writing lead sheets for pop songwriters; you write a song, you have me make a lead sheet, and with a simple recording, you are good to go.
(Lead sheets became so much the de facto copyright submission medium that when I was hired to write lead sheets for John Williams’ full-orchestral scores for Star Wars, I convinced 20th Century Fox studios that a Xerox of Williams’ scores was a much better CO submission. I lost a lot of money on that one.)
Consider the circumstances. Neither of us had ever heard any of the Hotel California songs. We had to hear them for the first time, transcribe the melody, harmony, and lyrics on to paper, using pen & ink, into a sharp, graphics-quality, camera-ready master that could be reproduced (no computers or digital printers, remember) and was unambiguous, enough to sustain any likely copyright challenges. Can you do that in less that 12 hours?