Is it true that Democrats used to be the conservative party and Republicans used to be the...

Yes, the history on it is pretty clear. The first answer in the link you posted gives a pretty complete answer on what happened. The conservative party of states rights and small federal government used to be (drum roll) the Democrats, the party of social justice and government expansion used to be the Republicans. There are plenty of pretty complete explanations to this, the final moves of the switch could be traced to the Democratic support for the civil rights movement, the Republican Southern Strategy and really showing the beginnings of our current state with the Goldwater candidacy.

http://www.livescience.com/34241-democratic-republican-parties-switch-platforms.html

http://www.npr.org/sections/codeswitch/2014/07/14/331298996/why-did-black-voters-flee-the-republican-party-in-the-1960s

https://en.wikipedia.org/wiki/Southern_strategy

PO1 William "Chip" Nagel thanks for this most interesting read/share!

well Not exactly... they were the Party of the South and domination and the republicans were more of the generous type and were willing to work together...
they drifted apart and in different directions...
thanks for the Share...