I would be very careful with Acetone... I ruined the front panel of my Quadra 950 a few days ago.
However, a couple things that I did discover as a result are that Rust-oleum "fine-textured" spray paint very closely matches the original texture of the case, and Testors Flat Light Aircraft Gray spray enamel is a near perfect match for Macintosh Platinum. Both colors lay between Pantone 420-421. This will also come in handy with another project I'm working on. I have an SE that I had to use plastic filler to repair many deep gouges to the case, and I've been trying to figure out how to restore the texture and color.
Next we'll see how a custom ordered rubber stamp (which I Photoshopped with Apple Garamond, and perfectly aligned and sized) works to restore "Macintosh Quadra 950" to the front panel.