Barracuda FB Rear Quarter Glass Sticks

Dear FABO - have a 68 FB, the rear quarter glass will go down but often stick on way back up, the only way I have closed is by using a lot of force (probably too much, so I just leave the glass in the up position)

My question - - does anyone know the process to remove the interior rear trim in order to get access to the window regulator mechanism?

Thanks