Just for information, it works much better to separate the headlight housing with a heat gun. because heat can be added were needed to separate the sealant and one can heat only were the sealant is to avoid damage to any other part of the housing (especially the clear piece because when heated to much will turn a yellowish color.) then went resealing the heat gun works in the same way, just reverse of disassembly.
I disagree with not scuffing the surface. Any time paint is used the surface underneath should be rough to a degree. without it being scuffed the chances of the paint chipping and/or flaking is much grater. (abrasion is not necessary to create chipping or flaking because of the constant heating and cooling the headlight goes through.)