I think the Warranty only applies to the person who bought the GPU from AMD.
Likely anyone claiming Warranty on CPU will be asked to provide proof of original purchase from an authorised retailer.
I have not had to claim Warranty on AMD or Intel CPU so I am not 100% certain.
However that situation does apply to Warranty claims on AMD GPU.
I know this because people selling GPU on EBay often claim the GPU is "Still Under Warranty" giving purchaser the impression if they buy it and something goes wrong, they can claim Warranty on the GPU.
It is actually Fraud.
Likely there is a database that can link CPU to original purchaser.
So be careful what you do.