No, it is very easy to spot. The fake news and comments in social media are consistently identical to what is published in state controlled Russian and Chinese media. At the very least, this is highly suspicious.

But of course, they do it skilfully, plausible deniability is the name of the game.

I recommend reading "The Red Web", "Nothing is True and Everything is Possible", and "This is Not Propaganda" to learn more about this phenomenon.