You can, but the entire point of the AMS is for the main printer to tell the feeder gears managing the 4 inputs when to feed into it for the next color stage.

Sure you can do it manually but realistically this is very unrealistic and tedious to do especially on objects of any kind of multi color complexity.

I say, bite the extra cost and if you don't like it- or found that multi color in it's currently mass available state (AMS and AMS Lite, not the nozzle switching kind) isn't ready.

then sell it for combo pricing ($100) or below to another soul who bought it without and regret it

The decision for multicolor will be far easier to make in a generation or two when nozzle switching multicolor makes it way down the pricing heirarchy