You're right – this depends a lot on context. For example, I'm not sure if theater companies would use the same terminology as software companies. (And that makes me wonder: would dress rehearsal be considered a synonym or an antonym for dry run? It seems like it could be used either way – maybe more of an antonym if we used full dress rehearsal.)
Another option that came into my mind was D-Day. In addition to its historical meaning, NOAD provides this definition:
D-Day (noun) the day on which an important operation is to begin or a change to take effect
It wouldn't be a universally-applicable "antonym" for dry run, but I've heard it used every now and then to refer to a momentous date requiring a lot of coordination (say, a wedding day). I found one message board where a contributer used D-Day to refer to the day she'd quit smoking1. The Independent used the term in a business context2:
Argos is gearing up to be able to stand on its own two feet after being demerged from its parent company, GUS. D-day is on Wednesday, when shares in ARG ... will trade as a separate company.
So, it doesn't seem like too much of a stretch say something like:
We'll have a dry run on the 23rd; D-Day is on the 25th.