At $160 per spring, I would check Eaton Detroit Springs and ESPO for the cost new. If you ask (and if they listen), Eaton will set up the springs to look original.
http://www.eatonsprings.com/ http://www.espo.com/ Or, check out Chevy Duty, Jim Carter, Chev's of the 40's (or many other parts dealers).
Of course, if they ain't broke (or lopsided), do not mess with what you have.
Tim
