Yep. Used during litigation, there is actually documentation listing all the artists who suffered master losses. It's a huge list, and Peggy's name is indeed among those included.
For us, the biggest hypothetical loss is "The Legend Of The Well," a song that Peggy is said to have recorded for her album
Sea Shells, and which never saw release. However, even before the fire, attempts at locating that master had been unsuccessful. One possible explanation is that, despite its listing in official session documentation, it never really existed: Peggy could have ultimately cancelled plans for its recording. Another possibility, which I'd like to think likelier: the master could have been lost (misplaced) somewhere in the vaults, and thus in need of retrieval at the Universal Studios. Too Late Now.
We also lost whichever alternate takes and studio chatter Decca might have preserved in its vaults.
Ivan