[Marshall V. Daut]

Look inside the exhaust manifold ports. If you can still see recesses for the gland rings, you are o.k. to use them. Consider that these narrow rings fit inside the manifold, pass through the thick gasket and then nestle inside the engine block recesses, which should still be there. If the manifolds were trued to such an extent that the exhaust port recesses are gone or barely visible, then gland rings will not work. Otherwise, try them. You will be able to tell while tightening the nuts whether the gland rings are binding.
But before you do anything, check for straightness across the tops of the exhaust manifold ports. If #4 is drooping, you're just wasting your time with ad hoc "fixes". No amount of bulletproof gasketing, sealants or torqueing the nuts will help. The extreme pressure of the exhaust will eventually blow out the overhanging gasket on #4. Trying to straighten the manifold in an oven usually results in it returning to its warped state because of its "memory". Now that you had both manifolds planed, if you order a new exhaust manifold as Mitch recommends, you will also need to order a new intake manifold, unless you have one lying around that has never been trued. Your intake is now too shallow to mate with a new, thicker exhaust manifold, which will result in a gap between the intake manifold ears and the engine block.
Marshall