CVS might work for the existing devs, but it can be a non-starter for onboarding experienced developers. Avoiding the upgrade to modern VCS tooling would be a deal-breaker for me, despite any other potential upsides. I view it as the tip of an iceberg of outstanding technical debt.
I think you focus on the wrong thing. If your code is good, just send git diff to the mailing list and watch it being commited. Tools used is not some kind of magic pixie dust ...