Short answer: No. Long answer: HELL no.
While GrilleGraphics.com is 100% color-managed from proof to print in-house, there's absolutely no accounting for what happens outside our four walls with regard to artwork and color. That said, we (and any other honest company, for that matter) can not say that we will 100% match the colors you expect every single time. Anyone who says differently is lying.
The color and brightness on many (read: most) consumer-grade monitors and printers are skewed one way or the other -- usually far brighter than "real world" situations. Moreover, subjectivity and plain ol' human nature prevents any meaningful discussion of color in the first place. What may look "too purple" to you might look "too blue" to someone else. And don't even get us started on lighting variations. The same print will look entire shades different under different light sources. Fun.
That said, our printers offer the widest color gamut (range) in the industry, so we offer the best possible opportunity for getting a "good" match, right out of the chute. Nobody has the tools we do (three printers ranging from six to twelve colors each), so nobody offers the range of prints we do. And while it is possible to get very close 99.9% of the time, if you're looking for an exact match for the finish on your kit, our recommendation is don't bother. There's a chance you won't be happy with the results, and we don't like unhappy customers.
The bottom line is this: if close enough is good enough, order away! You won't be disappointed. If you're looking for a spot-on match, we'll give it a shot, but it may not work. And if it doesn't, we told you so! :)