Hijack is not required - ntpdate could be started through a modified/replaced init file, the way things used to be started before Mark gave us Hijack. The Picker (allowed you to pick from 4 options of stuff to start at boot) was one of the most common stuff run that way, and a search for that should provide plenty of leads on how to replace the stock init file.

But today I'd go with Hijack. Easier and provides a lot of additional features.

Yes, the stock kernel also reads the config.ini file (for instance favorite visuals), but of course does not use/understand the stuff/options added for/by Hijack.

/Michael