Hey their chris15,
If you take apart the gauge cluster cover the gauge unit itself has a piece of Plexiglas in front which is fitted right up against the cluster cover itself, and fits over the gauges themselves. I wouldn't have known that except I had to stare at my completely striped dash while I redid all my new interior paint here a while back when I did my audio set up. Here is a picture to make better seance out of all of that.
If you just want to change the color to blue, I would probable better try to attack the plexi first, and see how that comes out. What you can do is special order a small piece of custom blue tint from any Tint Shop, or online which may be a bit on the expensive side to get, but in that quantity probably not too bad. You can also try transparent paint over it as well which is easier, but you run the risk of having to scuff the surface a bit to get the paint to adhere which if not done right could mess up the part, and unlike the Tint Film, is not as easily reversed. That's what I would do to archive the look anyways. I have been thinking about doing mine either in a really light orange tint, or smoking them myself on my ride as well, but I also have another project my friend really wants to try by making a whole new cluster plate out of either stainless, or diamond plate which would house aftermarket gauges allowing for more options of customization. Still a ways in development, but the idea is in the works for sometime in the distant future.
Anyways, hope that gives you at least a little better idea. Best of luck, and please let me know what direction you decide if you do it, and as always, I along with all the rest of us PT Peeps around here love Mod Pic's, so you know the drill.
Go easy, and I'll catch you later.
Candyman