Yes they do. I purchased both of mine from Design Specialties. You can get them with Z06 etched in them. They are probably the highest quality, and most expensive on the market, but their stuff is good!!
You may also want to check supporting vendor www.c5store.com. The carry a polished stainless steel cover that looks really nice and is about half the price of Design Specialties.
Check this one out as well. I'm surprised that Zip doesn't sell this anymore, as I got mine from them. Ecklers sells these as well. In their catalog they say that it'll fit all C-5's except the Z06, but this is not true. Fits perfect and it is a 'hard mount' cover. It just doesn't sit over the intake like others I've seen. You can also get this direct from the manufacturer: