Hi guys, since this DRM-FREE thing is popping up, i've have some questions with some games that i've acquired in the past. These games are from the Fallout series and i dont know if they are DRM-FREE on steam. If not, can i bring them to GOG so they can turn into DRM-FREE ?

No. That's not how this works.
You need to buy them here on GOG.

I think you have a wrong perception of what GOG is. It's a storefront first, just like steam. So, the game you purchased on Steam won't magically become DRM-free by "bringing it to" GOG. If you want DRM-free games, you buy those games on GOG.

If the products were identical, you would have no need to purchase it again on GOG, for they would be the same. But GOG is an entirely unaffiliated entity offering a different service. It might be the same good, but it is wrapped differently, and being sold to you differently. Approximately speaking, Steam offers you a revocable perpetual license (a rental), and DRM GOG offers you ownership. Ultimately if you wish to have the luxury of owning the game, as others have stated, you must pay the fee again. Even if they were the same, it would still work as it would with a physical good. GOG is a business with overheads that must store, market, maintain, make the product accessible to buyers, etc. You can't purchase a good from one vendor, then return it to another claiming that is faulty, etc. You may consider it not worthwhile to not replace games you have already bought, but that is your decision to make. I hope you enjoy your stay!

It depends on the game. You can't "bring" a title to the store (as in add it to your GOG account here if you own it on Steam), but if the game on Steam has no SteamWorks & other 3rd party DRM and works without the Steam client running, then its practically DRM-Free and you just back it up by zipping the game folder up. Fallout 4, maybe 3 & NV probably does have Steam DRM. FO 1-2 & Tactics are DRM-Free. PCGamingWiki is the best resource for this stuff:-
https://www.pcgamingwiki.com/wiki/Fallout

But do they have Fallout 1 DOS version? GOG seems to only supply the win95. I would like the DOS files to toss into a few low end machines.

edit:
Not literally asking for the game. I meant from gog to supply the files for both versions.
Plus I have no ambition trying to find the damn original in what random box around the house, may contain it...man, I gotta stop coming here after working hard xD