Is righteousness a prerequisite for salvation? James 2:24 NIV
  24 You see that a person is considered righteous by what they do and not by faith alone.


In James we are told that a person would be considered righteous by their deeds and not just their faith.  Is righteousness a prerequisite for salvation?
You say "a person would be considered righteous by their deeds and not just their faith".  I'm not sure this is a necessary reading of the Biblical passage. You quote 2.24: I think verse 18 is more useful for interpreting James' account of the relationship between faith and works:


  But someone will say, ‘You have faith and I have works.’ Show me your faith without works, and I by my works will show you my faith. 


James 2.18 (NRSV)

It isn't that faith and works are separately required – prerequisites, if you like – for salvation. It's much more that James sees them as inseperable.  You can't go round saying "I have faith, so ignore what I do: I've saved."  What you do, for James, demonstrates your faith.  If you have faith, you will do good works.  If you have faith in Jesus Christ, that faith will transform you and it will transform the way you act. A genuine faith is shown by the fact that the person does good works.  A faith that isn't seen in works is, as far as James is concerned, dead:


  For just as the body without the spirit is dead, so faith without works is also dead. 


James 2.26 (NRSV)

Or, as Martin Luther would have it (despite his well known views on the Book of James...):


  Faith cannot help doing good works constantly.


An Introduction to St. Paul's Letter to the Romans (1522)

James is reacting against a tendency – which has come up time and time again in Christianity – to ignore how Christians act because in Christ all sin is forgiven, or because salvation is predestined.  The tendency – commonly known as antinomianism (ἀντί against + νόμος law) – has been seen as heretical pretty much by all Christian groups throughout history.

I don't think James is undermining the significance of faith, but he is saying that it doesn't exist in a moral vacuum where it has no effects in a Christian's behaviour.