An article from April 25, 2019 that at least supports the idea that Bruce composed the "Western Stars" material prior to "Wrecking Ball," and that the album was "in the can" at some point before the "2016 River Tour" started:
https://www.jambase.com/articl...-album-western-stars
While the New Jersey native had been focusing on his 236-show Springsteen On Broadway from October 2017 to December 2018, Springsteen has been talking up a solo record in the press for a number of years. Longtime Springsteen collaborator Ron Aniello serves as co-producer for a project featuring material that pre-dates not only High Hopes but 2012’s Wrecking Ball. The album was in the can before 2016’s The River Tour as per Bruce’s 2017 chat with Jem Aswad of Variety. Bruce Springsteen noted in 2017 that this record “is influenced by Southern California pop music of the ’70s.”
But this still doesn't directly answer when "Western Stars" was RECORDED. It just indicates that Bruce had the songs written (or at least most of them) before he started "Wrecking Ball," and that the album was finished at some point before the "2016 River Tour."
I tend to be with you crookecrutch.....the vast majority of it was probably written and recorded before "Wrecking Ball," and the rest of the work was just overdubs and some spit and shine. Probably some remixing as well. I swear I read an article that had it all spelled out, and I just cannot find it.
I also saw a quote from Steve Hoffman's audiophile message board where the admin of Greasy Lake said that "Western Stars" was written and recorded prior to "Wrecking Ball."
https://forums.stevehoffman.tv...tars-june-14.833296/
I cannot seem to find the exact tweet.