You'll have to refer to the specific conditions of the offer. I haven't seen that offer, but generally offers are time-limited marketing campaigns. The time limit is generally short, like 3 months. AMDRewards.com says:
"Please note, the AMD Unique ID/voucher code must be redeemed during the Redemption Period for your campaign, after which the AMD Unique ID is void. See the Terms and conditions for more information."
Some terms and conditions say
"The AMD Unique ID must be redeemed within two (2) months of the end of the Campaign Period or [DATE] to obtain Application downloads after which the AMD Unique ID is void."
So you need to find the dates and instructions in the terms and conditions of your specific offer.