Bilstein did replace 8-year-old shock!
 

Well, it took about 6 weeks, but Bilstein came through and sent me a new shock to replace the leaking one purchased in '99.

One interesting note; I dug around the attic, and found the old original '91 shocks, and put one on the car (300SE) while I awaited the exchange.
The old shock seemed smooth enough, but it CLUNKED when hitting small bumps EXACTLY LIKE A BAD GUIDE-ROD.
When I took it off I looked it over, and found the bottom rubber bushing/grommet on the shock was pretty dry and a bit loose. Maybe that was causing the clunk.

So, before replacing the guide-rod bearings on a 126, you might check those shock bushings/grommets on the bottom of the shock. It wasn't too obvious, just a little play. The new shock cured it instantly.

DG