You do not need to match the order of your listed purchases with a site. You can add the purchase code in any order. All we need to ensure is that the same purchase code is not used more than once (as the same code will not work in more than one site)
Log into your support account, and navigate to the purchase codes tab to see the details of your licenses and the domains registered against them, however if you don’t see any license or domains listed there, you have the freedom to assign any of your purchase code to any domain from the scratch, this will not cause any issues with your site at all.
We have actually made a QnA section that provides answer to all your queries above which you can check out here => https://bit.ly/31L0Ebb