Sealant used under side marker gaskets?

[Dakota]

I had to use a small pick to remove the old gray gasket around the edge of my 70 Challenger's side marker lights.  There appears to be some black adhesive underneath that made the gasket removal extra special fun.  Is this black stuff just a leftover from joining the 2 metal pieces of the side marker body or is it needed for the seal to work properly?   I'm not as concerned about originality here as making sure the seal actually works. 

[jimynick]

It's probably some of the old 3M weatherstrip sealant that some guys used to glue the gasket to the bezel so that it didn't fall off/droop when they put them back on the car, back in the day. I don't believe the factory used any initially. 

[anlauto]

Factory used cement of some sort on those gaskets as well. I've seen black and yellow being used. I don't think it helped them seal as much as it just held them in place as mentioned