With reps I've learned to live with some occasional flaws. But QC is very important to me. I won't except watches with dust inside, scratched hands, crooked parts or malfunctioning movements. These I will send back immediately or I ask for replacement parts if it's not too difficult for me too replace myself. So yes, I'm picky
In your particular case I would ask the dealer to send a replacement dial, replace it myself and get rid off the dust in the process. If you're not skilled to do it yourself look for a local rep friendly watch smith and ask the collector to compensate your additional cost OR return the watch for a new one.