To make it a bit more clear. The page differentiate Researchers and Investors votes based on how their wallets are set up. But can historically be traced anyway.
Investor Vote: The page will show investor when the voter isn't a cruncher. Their wallet is running in investor mode. The page keeps track of historical CPIDs and can easily bee viewed as you say, by checking what CPID that has the address.
Miner Vote: When the voter has their wallet in mining mode. The page shows their username.
Linked/Unlinked Investor Wallet is a trial to track investors. It wasn't fully successful in the code I have now, but will be much more accurate in the next version. It links together addresses when spent together on the same transaction.
I'm very much looking forward to the new GCS!