Is the adhesive underneath the SD Card Slot Necessary?

I recently teared down my Aqua and Black original 3DS CTR-001(USA) to replace the SD Card Slot. When I followed the guide and pryed off the Slot off the metal board I found the adhesive all shriveled together and unusable because of my tool pushing it. Is the adhesive required for the heat sink of the 3DS or can the device function without it?