The old Fallout and Fallout 2 games were released before then vanished from the store and "recently" re appeared.
Is there any actual difference between them?

I bought them the first time and I still have them in my "my games", but the new releases show as not purchased.

Is there any actual difference?

Thank you very much. :)

There is 3 completely differ editions of first Fallout's
http://www.gogdb.org/product/3
http://www.gogdb.org/product/2
http://www.gogdb.org/product/1
Here the list of goodies.

I guess GOG Galaxy first builds is real Classic ones... Or not. There is no MAC Galaxy build for Tactics. All three MAC is not-native but emulated Windows versions. All MAC and probably all localized versions - are real Classic ones.
Current-latest Galaxy and offline build of Classic's is NOT classic. It updated by bethesda same as non-Classic versions. And it based on EU censored versions same as currently on store non-Classic Bethesda versions.

You should use oldest Galaxy build, or current MAC build (extract real Classic for Windows from package)(it based on pre-latest builds of Windows). Or pre-latest offline build - from torrents (im not find that). Or very first GOG installers on torrents - many live links. But that oldest setup do not have not only build digits (just setup_fallout.exe), but also do not have digital signatures - it is danger to download them from torrents.
Maybe some builds between first and pre-latest - but they cant be find as well, and no such info of correct file names.

Again, current version even for old buyers is censored, with Bethesda launchers - and not real Classic's. Although old buyers still have more content than newcomers to GOG.

http://www.gog.com/forum/fallout_series/fallout_have_i_got_the_censored_version
http://www.gog.com/forum/fallout_series/can_the_classic_fallout_games_be_played_on_mac

Not sure which goodies are missing precisely, but I had in mind such things like wallpapers, soundtracks, Fallout Bible etc. Basically those things that are under the Extras tab. IIRC Fallout 1 is censored (missing kids, but there's an easy community workaround), Fallout 2 isn't.

I didn't realize the newer versions were missing goodies. That kind of sucks : /

Do you happen to know if both the Fallout 1 "classic" release and the new release are censored versions of the game?

GOG Galaxy N/A and Mac builds (offline one) are uncensored:
http://www.gogdb.org/product/1#builds
same:
http://www.gogdb.org/product/2#builds
not sure, Mac online build are not exist\missing... should be same for offline builds:
http://www.gogdb.org/product/3#builds

All 3 Win offline - pre(!)-latest builds... Or pre-pre...? Not current ones, no. They almost same as non-Classic but a little bit outdated builds from Bethesda. Not from Interplay at all.

Not sure about very first builds from 2008. They ofc from Interplay, but probably EU versions with censorship. First builds and firtst gen. installers have number like that 1.0.0.4 (or any 1.x.x.x). Very first ones are numberless - just setup_fallout.exe. No GOG digital sign.
Probably some updated builds are better than first ones.
More better - find latest builds from Interplay, something before summer 2015...

Mac versions are not native ones from 200x years, but same latest offline Interplay versions builds packed in mac dosboxer and pkg installer. It possible to extract latest Windows uncensored version from Interplay from Mac pkg files that can be downloaded in account as Fallout Classic for Classic owners.
There is two native MacOS\MacOS X ports back in old days. GOG version is not true Mac in that case.