Guys the seller he didn't sold a Richard Sachs bike. He didn't mention that name at all.
He was selling a "vintage racing bike" that he almost never used. He said that he bought it 6 years ago from an other guy and thats all.
It was me the stupid that I was thinking that I can get a dream bike on this price from someone that doesn't know what he sells.
I was so excited that even when I saw it in real life I didn't want to accept that was not real. I ride the bike and I liked how I felt, so I bought it.
Even in legal terms the seller doesn't have any guilt.
This weekend I will try to refresh it a bit and to fix it on my preferences and I will start to ride it.
I will post a list with the components, together with my ride experience.
Thank you all for your replies.