2019 D Dime Is This MD On Both Sides

Looks like it to me.

Since the doubling on UNITED is toward the rim, there may also be DDD.

If your are looking for doubled dies, your looking on the wrong areas on the post 1999 dime reverses? Take a look at the areas you need to be looking at on these attributed dies. Then you will no longer be spinning your wheels searching for something that is not there:
http://www.varietyvista.com/07%20Ro...Listings.htm
Note there are few DDR's on many years on the post 1972 area dimes. So take a look at the post 1999 listings and see what areas are affected by DDR's and then consider this: "If this was a listing that year/mint, maybe there are new ones not found yet?" so consider looking at what areas are affected on each of these underlined years/mints and then you will know what to look for. (Why is this different than other years?) Because the newer doubled dies are from a new process that started just a few years ago. It is called a the "Single Squeeze Dies" and the doubled dies tend to be more towards the centers of the devices, rather than on the areas of the past die creations. Same with all other dies, but other years changed at different times. Some started at different times. So it was not an quick change over. But gradual. But if you keep looking on the areas you are looking, you will find Machine Doubling and die wear towards the rim directions. So stop spinning your wheels and train your eyes on the areas where listings are really happening. Then you eyes will know what to look for and you can stop guessing. (but it's your choice)