I've written a tool to extract the version info from a firmware zip (4.7.10413+). It can be downloaded
here. On windows, just drag either the update zip, KoboRoot.tgz, or libnickel.so.1.0.0 on to the kobo-versionextract.exe. It extracts the real release date (the URLs have been inaccurate recently), the version, and the revision.
This tool should make it easier to check for this kind of thing (where kobo has misleading update filenames and URLs), which has been happening quite a bit in the recent versions. It's almost as if Kobo is doing this on purpose to mess with my firmware page

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P.S. That same repository also has other tools (and more coming as I find a need for them), such as kobo-find (finds the path to a connected kobo device, useful in scripts) and kobo-info (gets various information from the kobo).