Sri, sorry, but I don't know the answer to your question. You can contact the center where you would buy the voucher and ask them.
Anut, why would you want to do SCJP 5 if your company is buying an SCJP 6 voucher for you? The difference between SCJP 5 and 6 is very small (see the FAQ), and SCJP 6 is obviously newer. I'd recommend you do SCJP 6 instead of SCJP 5.