Hi Mesh,
Yes, I found out months ago (6-7 months) that they were doing 'extra checks' on my and my dependant's background and are "waiting on the responses of external organizations to get back to us" (Comprehensive Security Screening). Only in the past 2 weeks have I discovered my Eligibility has passed. This was likely a result of the RPRF request and Schedule A requests we received mid-Aug, 2019. In addition, I was very open when submitting for Express Entry regarding a situation which would have lumped me into CSS fairly quickly after submission.
Regarding your question, I would recommend applying for CBSA notes, they give a more in-depth breakdown of your application than GCMS notes. If you think there is a chance you are under comprehensive SS, I would recommend applying for them, for peace of mind at least.
Cheers,