Here is a picture of the bucket and the headlight unit.
A new chrome ring (see first photo) comes with the bucket, that attaches to the sealed unit using little clips - (see second picture). You then locate the ring into the bucket and there are N/S E/W adjusting screws to get the levels right, and a locking screw which holds it in place. When you want to change the H4, all you do is undo the locking screw and slide the unit out the adjusting screws, re-lamp and away you go.
I bet the ring on the sealed beams is a bit mangled.