72 Charger. Instead of having little tacks/cleats on the drivers and passenger side at the top of the sill where the headliner tucks in.. there's just a lip that you're supposed to glue (?) the headliner too. At least that's what it seems like after taking out the old one. However it's unclear to me what is the best adhesive to use or even if an adhesive is used. Could really use some guidance here.