W124 wagon rear strut upper bushings

[E320wagonJack]

I am replacing partially failed accumulators and changing to a E500 rear sway bar on my 95 E320 wagon. I inspected the upper hydrostrut mounting bushings per recommendations on this site, and sure enough, the bottom halves were toast. I have owned the car only 6 months- my first Mercedes. I have considered selling it because of excessive road noise, and I suspect some of this is the failed accumulators and the resultant failed strut upper mount bushings.
On inspection, I can see that the strut rod has been contacting the edge of the hole in the floor pan- likely a big noise transmitter, and the noise that dissappoints me in the car has been a floor drumming sound whenever going over even modest highway cracks, etc.
My question: The combination of upper and lower halves of the upper rear strut mount don't show an obvious design to maintain the rod in the center of the floor pan hole. The floor pan has a mild stamped depression to match the bushing from the interior side- is that all that keeps the mounts from drifting and letting the rod contact the floor, or have the rubber parts deteriorated so badly that a centering shoulder is missing? There were some small broken scraps of hard rubber sandwiched between the halves- is this the remnant of an additional collar or insulator?
Local MB dealer states these rubber parts must be ordered from Germany- any tips on finding them quickly so I can get wife's car back onthe road this weekend?
Thank yu so much for any advice. This site has been fantastic!