And that was before the FBI had NSA's data on US citizens. The FBI's version of X-Keyscore has a different name.
We only know about COINTELPRO because some mysterious group of activists stole a bunch of the records from an FBI field office in Pennsylvania!
I suppose they could have gone for extra-legal methods, but after so much time the people with the motivation to make that happen (if it was possible at all) would have mostly retired too.