I can't for the life of me get a good picture. I'm sure I have some die deterioration going on here, but I still don't have the expertise to diagnose this. The bottom of the olive branch got my attention first. Is there notching there, or just wishful thinking again? I will try to get better pictures if anyone thinks this is worth pursuing.
Die Doubling or Strike Doubling? Hmmm.. these look like strike doubles to me instead of actual die doubling. But look real careful.. With many coins the differences between die doubling and strike doubling can often be spotted. Strike doubling is a much more common, often random occurrence and you should be able to spot it by examining to see if there is a step like feature in the reliefs that causes one relief to be higher than the other. I believe this is what you're asking? Since die doubling affects the very die that is used to strike every coin, they will all look exactly the same and therefore form a certain die variation. In this case the dual reliefs will often be at an even height. These can be valuable to collectors although I am unaware of any such die doubling for a 1999 dime. Anyone know about this? I'm thinking it's a strike double if it's anything.. Like I said though, it sure is hard to tell in a photo, and I might be wrong.
I don't see any of the flat shelf-like doubling anywhere. It just seems to be thicker than usual, maybe the die deterioration. Sometimes I read about "spreads" without notching, was wondering if this might be. Would it stand to reason that if the bottom of the olive branch were notched, then it would also appear somewhere else on the device?
