NO, you should not. You dont want to add anything that enhances gloss. It will streak like crazy and wont leave a uniform finish.
That goes for wash/wax products as well.
Chemical guys makes a matt detailer, but the only actual protection/wax that I know of is Swissvax Opaque wax. I actually waxed a matt black Menz last weekend with it, and its such a joy to use. but its around 200 dollars for the pot. The owner of the Benz bought the pot himself.
you better look into matt finish's before you touch a customers car. if you use a foam pad and even a non abrasive polish you will scuff the paint and if will leave gloss. you can not touch these paints as far as polishing.
You CAN clay them though.
swissvax and chemical guys offer good products for this. I would call them direct for instructions if you have no experience using them. I for sure wont give out advice on how to do it, because of the variances in these new finish's. Some are more sensitive than others and use different technology to get there. I'm most comfterable working on the matt vinyl cars as Its easy enough to just replace the vinyl on a panel if you screw it up. lol
For washing the car I have found that most rinseless wash's work well (even though they are said to have gloss enhancing polymers), they do not streak. As does poorboys waterless wash.
fortunately I have maintained a vinyl wrapped car for the last 2 years, so I got my process and products down pat. I would hate to learn on a car where a panel cant be replaced and painting it is the only option (matt clearcoat).