Rebuild, remanufacture, and even the common usage of the word "restoration" processes will not return a Ford 2100/4100 family carburetor back to a close approximation how it would have looked as Ford bolted them to new engines. New 2100/4100 carburetors had parts using many different finishes.
I will state up front that most of my research involves the Ford 4100 used in new Cobras 1962-64 and 428 PI equipped 427 Cobras in the CSX32xx chassis range. While concentrating on O.E.M. Ford carburetors for those vehicles I crossed paths with many models 2V and 4V. The carburetors I found interesting are ones that were new car take offs (I have a few and have pictures of others.) and genuine made in the production runs new old stock carburetors (I have a few.) I found it interesting that a 2V and 4V carburetor assembled in the same time frame had the same finishes and color codes for any part or assembly technique they shared. Carburetors of the same engineering numbers assembled later not only did not have the same finishes and color codes but often not the same small parts. Said another way a 1962 engineering assembly put together in 1965 used some parts like a 1965 made carburetor would have.
To "restore" every 2100 or 4100 covering years of production with the same small parts as applicable and same finishes would historically be a mistake. In the 1980s there was a man that expended a lot of effort to return popular 4100 models for Mustangs to as close to a day one appearance as he could. I thought he did very well, especially with the two big die cast aluminum parts. Unfortunately his services cost so much, on the order of $800 in 1980s dollars, he did not do many before ending such difficult restorations. I spent some time with him one day and he was glad to be appreciated but he would not tell me how he deep cleaned the aluminum die castings such that the looked very much like new made instead of restored. The platings I did not need coaching on because I have by that time already dismantled a rare carburetor into collections of different substrates and finishes, hunted refinishers, and sent the parts off to get day one type finishes. It was a lot of trouble and involved several refinishers in multiple states. The finished carburetor sure looked like a new old stock one but I decided right then I did not want to go through that again.
As an example of how many different "appearances" there were I created this general list this morning based on a couple new car take off C4OF-9510-AL carburetors.
Aluminum die castings exactly as molded except for secondary machining operations. (Once damaged chemically or mechanically as cast surfaces will never look just like day one again.)
Brass machined and or wrought with no add on finish. (Once damaged chemically or mechanically as manufactured surfaces will almost never look just like day one again without lots of fine detail work.)
Dye: Dye daub or dip in black dye on just a small section of a part.
Dye: Steel stamped zinc plated then dipped, complete part coverage, in black dye.
Dye: Steel wrought protected with bright zinc plated and then lightly coated with pink dye.
Grease pencil mark, light blue color.
Grease pencil marks, black color.
Grease pencil marks, scarlet red type color.
Nylon? type thermoplastic natural (no colorant added - common reproductions are pigmented "white").
Paint daubs in a vermillion type color.
Paint daubs in a safety yellow type color.
Steel stamped protected by completely leached clear dichromate.
Steel wrought and machined protected leached clear zinc / zinc dichromate (most of the time a noticeable amount of iridescence).
Steel wrought and machined protected leached clear zinc / zinc dichromate with various depths of "color" depending on part.
Steel wrought and stamped protected by leached clear zinc / zinc dichromate (just a hint of iridescence).
Steel wrought and stamped protected with zinc plating zinc dichromated iridescent yellow conversion coating. (Common modern restored parts are usually deeper in color than original finishes.)
Steel wrought and stamped steel plated in bright zinc (no yellow, no gold, and no iridescence).
Steel wrought protected by gray phosphate and oil.
Zinc die castings protected with bright yellow (no iridescence) zinc chromate.