Those of you that have purchased the PC version of Rocksmith and find you are missing your CD Key please see the following Ubisoft Support Article for help. It outlines the steps you need to take when contacting Support for this issue.
Missing CD key for Rocksmith PC
Answer ID 17223 | Updated 10/19/2012 11:20
I have bought Rocksmith for PC, but I cannot locate my CD key.
What do I do now?
Some physical copies of the PC version of Rocksmith are encountering problems during installation. We apologize for the inconvenience caused and will provide any affected consumers with the "Guitarcade timesaver," which gives players instant access to all the Rocksmith mini-games.
If your Rocksmith PC game does not contain an activation key on a seperate leaflet, please click here to submit your request, if you don't have a Ubisoft account already you will be required to create a Ubisoft account to submit your support ticket. We ask you to use the following options to speed up the time needed to start the process:
Product: Select Rocksmith from the product drop-down list.
Category: Select 'Registration'.
Subject: Copy and Paste the following text '[Key Inst] Missing-lost'.
Question: Enter the store details along with a description of your problem.
Attachment: Please include a clear digital image of your receipt clearly showing the store details and the product.
Once we have the above information we will contact you as soon as possible.
We apologize for the inconvenience and thank you for your patience.