Have you noticed the 75-77 mid-motor or 76-78 Deere's front extruded aluminum bumpers always look to be silver in color? This includes the JDX's, 100 series, Liquifire, Cyclone and Liquidators. However, they always look black in the brochures and even the NOS ones are black. What gives?
I finally took the time to dig into this, and found out why. Deere anodized the bumpers black when they were new. However, it appears that exposure to the sun faded the color, leaving only a clear anodize layer protecting the bare aluminum.
Notice the 76 Cyclone bumper above. Under the stripe it's black color is not faded, but has the same texture and feel to it as the rest of the bumper. There is no paint layer under the stripe at all. This fading is probably why all the fire series sleds had painted bumpers, more fade resistance.
I hope this is useful to you...
-Joe Rainville