If you see a panel without a neutral buss, you can be sure it was intended as a 'power only' panel. Remember that in the days before the 2008 NEC, there was a distinction between panel types, with the 'lighting and appliance' panel being defined as having a large number of neutral-served circuits, and then went on to limit the number of circuits allowed.
In 2008, that distinction -and limit- went away.
In a split buss panel, there is a split between the two halves - but you might not be able to see it without removing the breakers. Typically, all of the busses are separate, with the single phase part fed from a breaker in the three phase part.
Though I need to be careful as to what I claim is 'typical.' I haven't seen that many split-buss panels- and all of them were old enough that the 'neutral buss' was a plate at the top, where you had to wrap each wire around a screw.
There is no barrier separating the sections, and wires commonly pass through the 'other' part of the panel.
