Yes, it should be answered and providing proof of buying/holding electronically not a bad idea either.
As a side note, and remember I am no attorney, I would assume you may still want to answer all charges, so your firm denial is already on record seeing the case was dismissed in such a way that there is a slim possibility it could be brought back up somewhere in the future(no worries for now and most likely will never be).
"Once in a while you can get shown the light in the strangest of places if you look at it right?"
- Jerry Garcia