I'm not about to go calling Disney Dining and being on hold forever just to find out whether or not the ADR has been deleted somehow. Maybe if they'd just get rid of the whole "press 1 if you've been to WDW before, press 2 if you have been to WDW in the past 2 years, press 3 if you've ever known anyone else who went to WDW" sort of thing you get when you call them.
If I were to worry about that, I'd have a printout made at the resort. (Resort concierge can print all your ADRs out for you). If they can't find the ADR you can have them make another one. You may not get the same one, though...but that could be true no matter when you check.
I would think if you call WDW-DINE just to check, it heightens the chances that the reservation will get screwed up somehow.