A fair amount of remarks do change, (20-25% result in a change of grade but much more result, about half, in a raw mark change) typically by one or two marks either way. Changes by much more are not unheard of (and more common in humanities subjects) but are very rare. I would say get your papers back and look through it with your teachers, though they may say not to bother since you're into your firm.
As above obviously don't bother with a priority remark, that's for people who need remarks in time for reconsideration by a university.