Hey Noibeau,
The answer is yes, with a caveat.
You can install Slice Machine on any project and use the SliceZone component by running the command prismic sm --setup --no-prismic (the --no-prismic flag skips the step for creating a Prismic repo).
However, the CLI commands like prismic sm --create-slice might not work, because your repo might not be configured for slice machine on the backend. (Repos created with the Slice Machine CLI are properly configured by default.)
If you retrofit a Prismic project with Slice Machine, and you get errors with CLI commands, you can send a message to the feature activation team, and they can configure your repo for Slice Machine.
Let me know if you have any other questions!
Best,
Sam