The 3 Fallout games have been re-released. I had them on my GOG account for some time, and they are shown as "Fallout ... Classic", while the new ones appear simply as "Fallout ...". Is there a difference?

I wonder that too. What's the difference between the Interplay builds and the Bethesda builds? Any plans to give the new versions for people who bought the old ones?

More importantly, are the games different enough that people should have to buy the games again to be able to access them?

One thing to notice is the "new" versions don't have all the extras that the "classic" ones do. No idea beyond that though.

Just noticed, all three of my OLD versions have been updated, more languages and, in fact, the old extras are missing in the re-releases, hm...

The "Classic" moniker just means the original GoG release. The Version in the store is different; it is the European version (no textures for the children) and has had the community patch (I think Killaps) and the HD Mod rolled into it.

Well intial GOG version ("Classic") is British, censored version, too.

The new release Fallouts seem to include only manuals as goodies, the classics have wallpaper, art, avatars, soundtrack and "fallout bible". I'm guessing the Bethesda doesn't have the rights to those. Classics also have the Mac versions which seem to be missing from the new releases.

I'm pretty sure the owners of classic versions aren't missing anything but vice versa. I hope the GOG manages to get all the old goodies for new buyers too at some point.

It is, check children, for example.

My installs are patched and moded into oblivion anyway, I'd have to do a fresh install.