Peter, most ball bearings used in Pantera rear uprights are weathersealed either with interlocking steel shields or with poly shields to make them weather-tight if not water-proof. Those tin extras don't do much to improve this. If the bearings that you're using are shielded, you really don't need the extras. On the outside, using them might force a slightly deeper bore for the bearing so the 4-screw retainer fits flush against the new bearing. Incidentally, pressing out on the stub-axle to remove it often bows the retainer into a shallow cone and it then doesn't fit flat against the bearing. So get a nice big hammer and flatten any retainer you buy if it looks bowed. The flathead retaining screws are std metric and now there are gr-8 flathead allens available. U.S Pantera vendors have used OEM retainers & new screws in stock. Some use LOck-tite on the 4 screws but that may be overkill; when torqued, they seldom loosen up.
BTW, the outer bearing locates against a step in the upright bore and the retainer holds it firmly in place. The inner bearing floats according to the length of the sleeve between the inner & outer bearings, neither of which were pressed into the upright. So as you say, without that 4-screw steel retainer, the entire outer stub-axle could have begun moving in & out of the upright! In a car with the speed and cornering capability of a Pantera, leaving that little 4-bolt retainer out verges on criminal neglect! You are one lucky boy!
