The manuscript scores of Lully's ballets provide almost no information regarding scoring.
A recording released in 2006 used a text based on Elgar's manuscript score rather than the published version.
He never added these into the one and only manuscript score.
However, Tchaikovsky was so dissatisfied with his own version that he later destroyed the manuscript score.
Regardless of the exact circumstances, the manuscript score remains lost.
In 1879, Tchaikovsky asked for the return of the manuscript score.
Have you ever seen one of his manuscript scores?
The manuscript score of Orpheus was not rediscovered until the late 20th century.
Nevertheless, the manuscript score survived except for the last two pages.
The 1898 revisions were in fact so extensive that Mahler had to write out an entirely new manuscript score.