91 300SL Replacement Blower Motor adapter needed help

[hnysfan]

Hello,
It is always good to count on the very valuable help that forum members can provide (and I hope that I'll be able to help as well in the future).
I am replacing the blower motor on a 1991 300SL, the new motor body is shorter than the original by about 12mm, there are notes on the parts suppliers indicating that and adapter use is needed to make up for the difference in length of the new motor.
"Effective with 9/1996 production the dimensions of the blower motor have changed. The overall length of the new blower has been shortened. The new blower will not seat properly unless the adapter supplied with the blower is used and the end stop in the blower housing is removed on models prior to 3/1996 production."
The problem is that although the pictures for the suppliers show the adapter piece being included with the blower, it does NOT come with it. We've contact the Dealer and they state to know nothing about the adapter being needed.
I vaguely recall doing the same repair on another car in the past where the adapter came included with the blower.

Does any member know anything about this or is familiar with this spacer/adapter part and knows where I could get one (the part in question is what is encircled in the attached picture)?

Many thanks in advance,
Ivan