I second this approach, very similar to what I am using: I keep this folder structure:
In case I want to reorder PCB of version “v0.9” I get all the gerbers and ordering information inside \Releases\v0.9 subfolder.
When I want to troubleshoot “v0.9” board, I find exact schematics, part numbers populated at Batches\date-v0.9 folder.
When I accidentally see possible way of improvement of last release, I go to \KiCad folder and modify project on the fly, append “Version history” text section in the schematics. When I accumulate enough improvements for PCB release v1.1 PCB release, I archive sources to \Release subfolder, and true assembly information in \Batches subfolder.