I have these .
It goes over your existing gauges and also changes the color to a white/blue-ish color, much better than the green, if you ask me.
They have the actual gauge color in white as well, here
I did read up on modifying the stock gauges before I purchased the reverse glow gauges, and apparently it can be done. However you do have to take off the needles and pull the gauges off...and sand off that green film that is on the back.
It's not very hard to get the instrument bezel off, you can take that off and hold it up in the sunlight. If it has the green tint to it, then it has the green film on the back. My 2004 has it. If it doesn't have a green tint to it, you can replace the bulbs in the back of the instrument bezel and change the color of your gauges.
Instead of pulling the needles and all that, I just bought the reverse glow gauges, stuck them on, plugged them in to the factory harness and now have cool blue-ish color gauges.