Wide S side deco installation- what the heck is PN 999.911.141.50?

I'm putting the deco trim back on my car. The parts book calls out "plastic sealing", part number 999.911.141.50, and it appears to go under the deco. It is sold by the meter and is listed everywhere as NLA. The English language websites refer to it as a "desk pad". My guess is that it acts as a spacer and/or cushion between the metal deco and the body. The illustration shows it to be fairly wide (like 2"), but it's hard to tell exactly.

And to avoid confusion, this is NOT the beading that goes along the top edge of the deco; this is a part that I believe is totally hidden under the deco.

So my questions are:

1. Anybody ever seen this?
2. Is it needed?
3. If it is, is there something that can be reasonably substituted if it is truly NLA?

Thanks for the help!

I've heard of it, but never seen it. Maybe it automatically dissolves in 30 days :confused:

If you've never seen it, then I feel pretty comfortable skipping it! I'll just go for the post-30 days look right from the start.

Umm...
what year car you working on?

Perhaps it's like a double-sided tape that was used to hold the trim along its length and prevent rattles, etc? There was some tape like this holding the wood/alloy dash pieces on my car...

Could be similar to the Terrostat putty tape used on the fenders and under the rear quarter window bright trim, just wider.

The foam double sided stuff will hold moisture..bad idea.

It's a 73. Agree it might be some kind of double-sided tape. And yes, definitely want to avoid anything back there that will trap moisture.

You can use 3M "dum-dum" rolled and flattened. It helps prevent water from penetrating the screw holes.

I finally dug out my original side deco to see if this material was still there. Sure enough, it was. It's a small square, about 1 cm on each side, on the back side of the deco at each of the lower holes. It may have initially served a moisture-prevention function, but it's so stiff now it wouldn't provide any sealing. Or it may be there just to elevate the deco off the rocker slightly to avoid scratching the paint. The "tape" is about the thickness of two or three layers of duct or electrical tape. Which might just make a suitable substitute...

Isn't the "Desk Pad" the same stuff used under the front scuttle grill?

I thought it was there to stop you denting the trim when fitting the screw?