First, we're going to specify that this is regarding pickup truck bed liners.
Second, historically it's been found than anything short of anodizing the hilts will wear off over time. Unless, I suppose, you put the color on and then never touch it again.
I'm really surprised I didn't get any strange results when I typed "liquid bed liner" into Google, *whew*.
To the OP, you're certainly onto something in that spray on formulas like that are made for heavy duty, but as Sakura said it won't last forever. Are you dueling with your saber? I mean if you're just interested in display and light wear and tear then it should last a long time.