If our clients would send us all the pages, we'd usually have the information we need.
CT requires 50% or more of a fund to be CT-sourced before it's CT tax-free, so I scan the "funds" page if available, but I don't worry if not. (I seldom see more than a couple % attributed to CT.) I just put it in the CT-taxable column.
If a client purchased bonds from municipalities and those pages are missing, I tell the client to get me that information. Most of their brokers use mostly bonds from CT municipalities, state public works, etc., so there's a lot of income that can be exempt from CT tax.
I warn my clients that inherit investment accounts from mom/dad who lived in NY or FL or other states to talk about the investment choices with their own financial advisors soon, discussing things like risk-tolerance and state-sourced funds and municipal bonds.