This message was posted on behalf of Intel Corporation
You should be able to get this information with the FPO number, see this link for an example HOWTO: Read an Intel CPU FPO/Batch Code .** Usually, that numeration is on the back of the processor, once you have the FPO this illustration will help to get the date codes.
For further reference Frequently Asked Questions about Intel® Desktop Processor Warranty
**The content on the above site is not controlled by Intel. This information is offered for your convenience and should not be viewed as an endorsement by Intel for the merchants or services offered there.