Yup. Recently GOG has started to offer updates too, in those cases where downloading a 10 MB patch might be more preferable than downloading a whole new multi GB installer just to get the latest patch.

The game already is the latest (and, very likely, last) version. No need to update.

The installer currently available for download has the latest version now. It'll get the new installer some day (since it has the old 1.0 installer at the moment, and all games will get the new 2.0 installer, I think the plan was to have all games using the new installer before the end of the year), and perhaps the game itself may also be updated in the future.

Thanks a lot for putting up with my b.s.

Just to be clear, the only benefit of an updated installer is so that the game installs faster? Or are there other benefits?

The new installer by default installs the games to C:\GOG Games rather than C:\Program Files\GOG.com, since many games have problems with Vista's, 7's and 8's protection of the Program Files folder, it also remembers the last folder you installed to (if you like to install the games somewhere else) so after installing one game with the new installer, the rest goes to the same place by default.

There are a few other changes (apparently better compatibility with Windows 8, DPI-aware, ... ), but I think those above are the most important ones at this point.

It remembers install location? Where does it store that info then, hidden in the registry somewhere? I'd quite like to know where the installer stores info.

That's not what I was referring to, but close.

HKEY_LOCAL_MACHINE\SOFTWARE\(Wow6432Node\)GOG.com\DefaultPackPath

(...) only applies to 64-bit Windows