I wouldn't touch a 1916 D unless it was slabbed. There still coming out of China in various "circulated" conditions ...
Though I happen to own a 1916-D Merc with an added "D", I am not the worlds leading expert at detecting counterfeits. Three things bring me pause with this one. This is a well worn dime. The rims are worn flat. I believe the mintmark is too pronounced for a coin that worn. Secondly, I know that mintmarks were hand punched and can be in different locations, however this one appears too high to me. And finally, these days even a well worn 1916-D is an expensive piece. There is a reason that dime is not in a slab. Myself, I think I would pass this one by.
4 different MM positions, this could be one, but might not, either. I would not consider buying it based on those photos. obv is scrubbed too.
From that distance it looks okay - But we need a close picture of the D to see if it was added or not. I had one which was slabbed that had similar wear. Even the "D" which is set lower than the branch and the rim looks about right. That being said if you would buy one, it automatically becomes an investment, so slab is safer than not slabbed
This is hardly "a premium grade." if it is genuine, it would grade a strong Good. With today's "grade-flation" it is now a VG. That's still nothing brag about. I sold one in EF (full ax lines) when I was dealer to a want list customer. It was certified, and I would not buy one of these coins, especially over the Internet, if it is uncertified.
Have you already purchased this ? If so, I hope all works out for you, and you have learned something valuable for your efforts.
I have reasons to question this coin as being genuine. @Randy Abercrombie clearly listed a few of them so I will not elaborate. In AG-3 this is a $300 dime if slabbed. The condition of this coin is higher than AG-3 so why is it raw? Please avoid and do yourself a favor.