The plastic at the back of the dials can either be orange or clear plastic, fortunatly for me mine was clear so whatever colour bulb you put in, will show through white or clear backing on the dials.
The metalmonkey dials that Ive fitted to my car went in pretty easy, the only tricky part is getting the needles back on in the rite place, but the instructions that you get with the dials guide you through, step by step, so its not a hard job.