The beloved lightweight distro
It is licensed under the GPLv3, and is not currently in the AUR. (However there is an older, unmaintained version, under a different maintainer and repo.) https://aur.archlinux.org/packages/wlclock-git
In that case you probably want to request to take over the existing package.
No need for approval from upstream as the GPL freely allows redistribution.
Except the AUR does not normally count as redistribution. It distributes package automation scripts and patches. The source/binary is typically download by the user from the official distributor when they build the package. Some packages do include source/the binary, but most do not.
Distributing the built package might cause issues for some licenses though (not the GPL though).
A takeover is only needed if it's also a -git package. Any other "type" is fine, but mark the packages as conflicting.
Edit: also keep in mind that -git packages don't need to be updated unless they're broken
You can request to take over the existing package if it's broken (-git packages tend to pull the latest version, so don't fix it if it isn't broken).
You are not expected to maintain it forever. However you should make it a -git package if you do not intend to update it on every upstream release, so it stays up to date without changes to the PKGBUILD.