The backup copies of The Witcher 1 and The Witcher 2 are the latest version of the game right? So if I install the latest Back Up I won't have to download any updates for the games? All of the patches are included in the Back Up?

If by "back up" you mean the installer file in the "My Account" section then yes.

If there are any updates they include a patch file and also update the main install file.

Pretty much.

Not sure what the behavior is when they include a separate patch, but when they don't you can be assured that it's the most patched version that they have.

My understanding though is that they include a separate patch to spare people from having to re-download the entire installer when the installer is big and the installer they provide is patched with the patch (making the patch redundant if you re-download the installer anyways).

Yes to the Witcher 1, but unless they stealthily updated the installer when they added the extras not so long ago, the Witcher 2 installer is still version 3.0 while the current version is 3.2. If it's still 3.0, you can find the two missing patches here and here.

I'd bet that it's still 3.0, honestly. Since it's been patched frequently (1.1, 1.2, 1.3, 1.35, 2.0, 2.1, 3.0, 3.1, 3.2), the installer here hasn't been updated with each patch like it would for other games. As memory serves, it was the vanilla version until 2.0, then updated again for the EE. Seems they only update it for huge changes, and 3.1 and 3.2 were minor.

You mean they didn't put the patches on GOG? That's odd. I assumed they would do something like they did with Alan Wake. With AW the installer has the version number (1.0) and there is a patch with its version number (1.3)

In their defense, the game should automatically update to the latest version if it's connected to the internet when you load it up after installing. On the other hand, that doesn't always work for whatever reason, and I'm sure it'd be appreciated if people could download the patches here in order to back them up without having to hunt for them on the main site.

Now, they did have the GOG-specific patch 1.1 up for download here when it came out, but after that the patch situation with the game got a bit out of control. Take 1.35, for example: If you had patch 1.1, you needed the specific 1.1 -> 1.2 patch, then the 1.2 -> 1.3 patch, then the 1.3 -> 1.35 patch, but if you had a fresh installation you needed the 0 -> 1.35 patch. This got even more complicated with the release of 2.0, which you needed to be updated to 1.35 for, and there wasn't really any way that they'd be able to indicate which patch was for who (since not everyone kept up-to-date) if they just included them as downloads. It would have been a mess and caused more trouble than good.

Well if they have an automatic updater, then all should be well.

However, I wasn't even aware that there were updates. I've been spoiled by Steam, which updates games without me even realising. Otherwise the old GOG games don't get updated at all.

I remember the old days of Half-Life updates so I could get the beta versions of Counterstrike working. That was a freaking nightmare! Especially on dial-up internet!!!