Change in LCA, New Amendment - Does require re-stamping?

[metaphor]

Hello,

I am working for one of the TOP 3 IT companies in India.
I came to the USA on my H1 (valid till Oct-2013) on April 2011 for a client A. By April-2012 I moved to a different client B - with a LCA Transfer and new H1B Amendment. I have planned for a vacation by Jan2013-Feb2013.

Do I need to have a re-stamping done before I come back to the USA?

Thanks for your time!!