EPC has a hardtop part that my car doesn't have

[Tomnistuff]

My hardtop never had a part that the EPC says I should have.  It is hardtop chrome rail item #21 left and right part numbers A1137950133 and A1137950233.  It supposedly goes between #25/26 which cover the B-pillar front edges and #19 which holds the side window vertical seal. 
Mine never had it so I can't photograph it, but it is shown on the hardtop exploded view in our Technical Manual.  Admittedly, the EPC lists it as NB, but I don't know what that means.  It is, however, illustrated in the hardtop exploded view as #21 in our Technical Manual, where Gernold's hardtop restoration is located.
I hope it is a part that was eliminated from the builds, because I don't want to go looking for the parts (left and right).
Does anyone have an explanation?
Tom Kizer

[Pawel66]

I think this may be a pad that we sometimes find between the rails. I have EPC in English - I wonder what was the German name of this part. NB means the quantity is not defined for a car.

If I am right - it was used to move the window frame (rail/seal) a bit forward on given side. We now use something we fabricate for that purpose. I used a piece of rubber on one side.

But what I say may be wrong.

[Peter h]

This part was only installed as required so that the side window rests well against the rubber.
Some have them on both sides, only on one side or, as with you, none.
Peter

[Tomnistuff]

Thank you all.  It is comforting to know that I have not discovered something else wrong during the restoration.  I can now continue with less concern about the results.  Things are going well, but slowly. 

You are very helpful and generous with your knowledge.  Thanks again.

Tom Kizer

[stickandrudderman]

Indeed, it's a filler to ensure that the window seal is a snug fit. I've just stripped a hard top that had only one.