Is there a difference between the Bioshock remastered being given away by Amazon and the version Epic gave away a while ago?

I'm wondering if I should try to trade the key on the trading forum or use it if there is additional content.

Well, Epic version only give you the remastered version of 1 and 2. It had, but last year November they removed the 2K Launcher. I'm not sure Epic version of BioShock 2 includes the Minerva's Den DLC or not.

But content wise its more than Epic version, since you get OG and remastered version of the games! Also you have achievements for remastered version via GOG Galaxy.