No. The 296 uses a traditional bank/channel architecture, while the 396 uses a far more flexible system/group architecture. In essence, you can make a "bank" just about any size you want.
It does take some getting used to, but once you do it's so much more flexible.
To answer the original question, no you don't have to have a dummy or blank channel in between the CC channels. IN CC only mode you can put as many control channels in as you want. The only problem with that is that if you are trying to track a multi site system, you run the risk of the scanner locking onto the "wrong" control channel.
Gary