Installing rear quarters

[BrugeeRT]

I noticed on some of the installation videos for the rear quarters, they a run a bead of either panel adhessive or seam sealer along the edge/lip of the wheel well before the quarter goes on.   Is this necessary or does it just get welded?

[AKcharger]

I didn't do that. most 1/4's come painted in "weld thru primer" so just weld away