Not that I know of, but ideas continue to trickle down, so I look forward to a reimplemention for Guix in the future. Something like nix-index would be great too, but all in due time, as the project admittedly doesn't have quite as many resources.

edit: to be clear, I'm taking about flakes, Guix does have plenty of mechanisms and utilities regarding direnv-esque project manifests, lockfiles, and even "inferiors" which let you install outdated packages that the distribution has otherwise moved on from by actually building and using the version of guix that the package would have been built with at the time