I find it odd that each control had a red and black knob. Usually the
throttles are on the same control and the shifters are on the other
control.

Maybe the guy just liked to alternate his knobs.

I have seen it done as you describe, but I personally prefer having a seperate
control console for each engine in a twin engine situation. There are so many
times when you are hoping to do something completely different with one engine
than the other that the physical separation of the controls makes it easier.

Example, if you want to go ahead on the port engine and reverse on starboard,
and if you transmission selectors are very close together, you need to be
careful not to whack the starboard control from reverse back to neutral as you
reach forward with the port.

For me, it's easier to "think through" the process (and I run single screws
more easily and instinctively than twins) when the controls for each engine are
together and separated from those of the other engine.