Bearings?

So I'm doing some brake work on my '68 Barracuda, and since the front drums are hubbed, I have to re-pack or replace the bearings (Yaaay!). I'm getting the feeling that I would be better off replacing them as the car has been sitting for ~15 years, but I'm not sure where to get bearings that will actually fit. Napa has quite a selection, but they all look slightly different from each other, so I just need help identifying the right bearings to purchase.