Yep. The CBA specifically for rookie salaries was huge.
The CBA didn't actually set the rookie salaries, and they still are negotiable. The CBA explicitly states that. The CBA also says the values of the rookie pool slots are supposed to be confidential. But in 2011, the NFLPA "accidentally" sent agents the entire breakdown of the rookie pool slots. That forced the NFL to send the same information to the teams, so everyone could negotiate on an even playing field.
Now everyone knows what each slot is worth, both in first-year money and in total contract value, based on the simple math involved with the various contract rules for rookies. Rookies (or, probably their agents) can and do still negotiate their contracts -- some manage to get more than their "slot," some accept less, and many are pretty much right on the dollar.
The end result is that it's usually much easier to negotiate rookies' contracts now, but that certainly wasn't by design.