Yes, you should remove the copper stud in your axle and place the new grounding piece in its place. They must have updated the assembly for some reason from when your car was built until when mine was built.
You Guys ...!
There is always something new to the community you guys find out about!
I did not know that. And yes, that's what the parts list of the 250/280 SL tells us (see attached)!
The old cap (copper?) 112 330 0057 was replaced by the new 108 334 0025 together with the (copper) contact spring 108 547 0085.
I don't know _when_ that was and since the parts list is dated Jan 1972 maybe the newer set 107 586 0033 is even different from the old repair set 111 586 0433 available back then. Very interesting.
Although I disassembled already three fintail front axles, none had these copper caps you described, Wallace.
Personally, I do not see the need that you change these (!) old parts with the new setup. Why not keeping the old copper cap and copper stud - if these still work properly? To me your old cap on the cap looks like copper not zinc (cadmium) plated.
This is what I did when I wanted to replace the front bearing kits of my W114 15 years ago:
I found out that only one of the four bearings in total (2 left, 2 right) showed signs of wear. All the other three ones were fine! I got the same 107 kits that you described above. Now I did not want to replace "everything" since most of my old stuff (3 bearings, 2 caps, 2 copper contacts and the clamping nuts) was still fine. I just bought a new separate roller bearing for the worn one and (!!) the two seal rings and put those together with the remaining cleaned-up old parts. And the overhaul kits? I have just kept those for worse times to come in the future...
When I overhauled my 114's complete front axle components two years ago I found the four bearings (remember: 3 old ones from 1971, one new from 1996) still being in perfect shape!!
If I were you, I'll keep the old copper caps and contacts - just for our successors to be shown how it originally was in the "old days"...
Achim
("Anybody in the need of two NOS factory original wheel bearing kits? No, just kidding, I'll keep them for one of my 3 MBs... )