CBSA notes is exactly the same as GCMS notes but without redaction! If you haven't received the other one, yes you can request a new one. I remember the same thing happened last December, when they dropped a lot of GCMS applications. It may have happened to you as well.
Yes, I got mine after ppr. from CBSA note, you can see the exact date the your SS started.
For the request, just ask them to release the information regarding your permanent residence application. Make sure to include your application number, UCI, etc. and make sure to ask them to release information ONLY regarding your PR application. Otherwise, they release information from every application that you had. For me, they released all the info about my previous study permit and work permits as well. The file was around 500 pages and it took them 2-3 months to release it