Sadly this isnt true. The original Literotica Story is amazing and at first they were just copying it but they felt like they needed to get the og writer credit and ask for its use but since it was such a long time ago they could not find them. Obviously it doesnt matter it was like you said 2006 but instead they decided to rewrite the story in their own style and it sucks ass compared to the og. So a promising 3d adaptation of a great porn story was ruined and turned into just another bad story generic MS incest game.
Note that copyright lasts much longer than 20 years. Also note that something is copyrighted upon completion in a recorded format (anything from handwritten pages, to recorded on tape, to video-taped, to saved as a computer file).
[Yes, I'm aware this is a pirate games forum. If you're going to steal something, you should at least be aware you are doing so.]
If the original author could prove they wrote it, then stealing it verbatim would in fact open one up to legal action.
In other words, if it was published (electronically) in 2006, that does matter.