You can do the guages, you have to disassemble the cluster and take the guages out and replace yours with them. Circles don't change shape for LHD to RHD
ALTHOUGH the mounting points are different, so you may need to modify it, I know we had to modify the one I had to get it to fit (The Tach)
But judging by you just saying "The green thing" I don't think you have enough knowledge to swap different guages, unless you have a lot of luck, cuz it can be quite a pain to do.
The green thing is the circuit board that transfers all the electricity around the guages. It has ground points, the little lights behind the guages screw/pop in and out of there, etc.
To disassemble the cluster you must remove all the screws holding it together and remove it from the front. The trip mileage reset must be unscrewed so you can pull the pieces over the knob, etc.