Thanks for the info, willwren. I'll plan to use SKF or NSK bearings that don't have those 2 rubber rings.
Since we're delving into "Bearings 101" topics, I'm also curious about bearing speed ratings. The nose bearings are to be C3 rated, and I always assumed that was a speed rating, but I began poking around the net to learn more about bearing ratings, and it seems that the C3 rating is a clearance rating, not a speed rating. So how do you select a bearing that has a specific speed rating such as 18,000 or 20,000 RPMs as needed for the supercharger nose?
'99 Bonneville SLE, white, 112,000 miles
'02 Park Avenue Ultra, white diamond pearl, 88,000 miles