No, DarkSend is definitely going to be an opensource project. We'll do some audits and make sure there's nothing wrong with the concepts and code, then open it up. By the way, it's going to be about 10000 lines of code you would have to add to your coin. It's not easy and you could destroy your coin by adding it. So good luck, this isn't like adding KGW. I don't think there will be many coins with developers that confident in their abilities. There's literally not one file that I didn't rip apart to do this.
DarkSend being opensource isn't that big of a deal, I've dedicated at least a couple years of full time work to making this coin successful. Can any other coin compete with a full time dev? It's the innovation that makes a coin like this successful and there's alot of ideas out there I can implement after DarkSend. We'll have one hell of a coin.
DarkSend is backwards compatible with the underlying protocol, so your dev that's working on the paper wallet need not worry.
You can put so much to rest by popping in and writing a few lines, I'm going to store the link to this post and quote it once a day,