USUALLY a BMW dealer upon seeing receipts that work was done will reset the lights for you for little or no fee. But if they are questionable and don't address all the required maintenance they won't.
Just for "peace of mind" you might just bite the bullet and have the major service done for 2 reasons:
#1) You'll know it's been done correctly & safely
#2) the previous owner was "maintenance deficient" and who knows what can go wrong further down the road.
Your conscience & wallet will thank you in the long run