If you had activated CS6 it would have been registered to your account during activation. If you sign in to adobe.com with the user ID and password you used during activation you should see the products have activated they get registered during activation and your serial number is also recorded so you can retrieve it should you loose number.
Adobe web pages have changes you may need to follow links to older products. https://www.adobe.com/account/my-products-services.html
I just tried use manage account link ----> View All Link ------> View Other Products link
View the following screens in a new tab so you can read then this site scale image poorly.
