To make the dampers, or nacelle clip tie-downs, or whatever their official nurnie-greeblie-thingie name is, I think I may have serendipitously (after three different attempts) figured out the mystery of the "missing piece": there is no missing piece.
The builder (who I think was Dave Beasley) of this subassembly simply "recycled" all available material, which were exactly these three parts:
From left, clockwise: 1.) Bandai 1/24 Messerschmitt Bf-109E4 Parts #B17 and B18 (5-step landing gear struts, ONLY the Bandai kit will provide this). 2.) Tamiya 1/35 Panzer Kampfwagen III Ausf. M/N (Kit No.35011), Part #C8 (Gun Barrel mount, and NOT part # A54 which looks very similar but is slightly different on top). 3.) 1/9 Kettenkrad manufactured originally by ESCI in 1975, and later re-issued variously by Ertl, Revell, Hasegawa, Dragon, or now Italeri, part #226P (or its identical twin #226Q). The trick is in a.) how you modify them (esp Parts 1 and 3), and b.) how you DON'T THROW AWAY YOUR CUT-OFFS, SCRAPS, or "extra sprue" lying around after modifications...
See those TWO little nibs that are cut off the landing gear struts on the wheel part? KEEP THOSE -- they become the "rivets" that later show up on top of the greeblie.
Now notice something else...
See how the landing gear top hinge section, that would go into the airplane (and allow the strut to swing in/out of the landing gear recess bay) is, when cut off, EXACTLY the width of the bottom inset of the Kettenkrad tow hook (Lower Right section of this picture)? That's not a coincidence either.
So you should end up with something like this, before you begin any major surgery on the landing gear struts' circular sections.
Then you should cut off the outside edge, on both sides, of the strut, using the natural angle of your clippers to where they "hit" the base but go back far enough to remove the "obvious" perception that this is a landing gear strut, and sorry for the crappy picture that is out of focus, but that's the only one that was remotely post-able. After this, you're going to sand it down using the SMALLER of the two sanding wheel options that come standard in your Dremel tool.
So that the end result...
looks something like this. What you're trying to do is "narrow the inserted section" enough so that it fits "perfectly" in between the opening of the Kettenkrad hook's negative space, so this is the trickiest part and so far I've never done it perfectly, even though I'm getting closer.
So before final modifications, it looks like this, but of course you have to build this on a dummied-up engine and nacelle core (L'eggs Pantyhose container, modified down) so that you're getting all the compound angles as close to perfect as possible. And then, the most delicate cut of all, which I have marked with a Gundam pen first...
That line/angle is crucial, because it is what creates the perception/illusion of a third/missing nurnie in this whole subassembly.
This is what it looks like "before" the correction for the nacelle nosecone angle, and the cut, and the final terrifying commitment of the sprue cutter...
And here is the rough-up, before gluing and final back section cut. See how it begins to look like the original subassembly?
Then you glue those little buggers on that you didn't throw away earlier, after cutting them way down to just tiny nibs/rivets, meaning you are just using the very tip-top of the leftover piece.
Looking familiar? We're getting there...
Meanwhile, on the UNDERSIDE, what you've done is cut off HALF of the landing gear top section, creating this:
And then, you cut off the very back top circular section, making it flush with the rest of the piece, and all of a sudden...
Viola! You have a musical nurnie that looks remarkably like the original...
Or at least, close enough for government work (make final clean-ups, adjustments, and whatnot with Perfect Plastic Putty or your preferred filler of choice.
Here's the original, for comparison's sake.
Has this solved the mystery of this missing mystery greeblie? I'd love to hear your thoughts, but I think it does, and I am mostly of this opinion because a.) hundreds of dollars of train bridges, cranes, track barriers, truck trusses, still girder bridges, and other steel-girder construction model kits later I still haven't found anything close, b.) this method explains both the 1.) strange spacing and 2.) different sizes/heights of the two top bump "rivets" on this particular nurnie, and c.) modeling putty of this type ALSO explains the indent in what would be a "puttied-in" section of the nurnie, since the putty of the 1970's putty was famous for drying out and "sucking in" as it dried, leaving little impressions or concavities like that found on the far left picture above.
Mad props and thanks go (again) to Dave Goldberg for his 3D printed version of the nurnie, which he modeled and which I used as a reference/template for making some of these guesses.