Yes, D will be OK. It's going to be a HEAVY tire but it'll be OK. Keep in mind that Treadwright tires are taller and heavier than a "new" tire of the same size. The retreading process adds about 8-15 lbs. to the tire depending on tire size and it adds some height too.
My father was running 265/75-16 Guard Dogs in the "D" load range and they were loud as hell on the road. Like, super swamper loud. But they were great tires. Everytime I've run Guard Dogs mine have been quiet but they were on other Jeeps besides wranglers and were a different size than what he ran.
~Lots of modded Jeeps and a Toyota 4Runner~
My favorite quote from the press release.. sad but true: "Chrysler claims its products, especially the Jeeps, can handle all sorts of terrible conditions, churning through muddy swamps, climbing mountains, and crossing rivers. Turns out they cannot even handle a car wash."