There are indeed two widths of the cush drive face. The later one is the one shown in your upper photo which is the more common version. The earlier narrow type is the sprocket in the lower photo. This early version uses a different sliding member which lives in a cup and is rarely used these days although I did sell a few of the early type sliding members when I was Singles Spares Organiser many years ago. I probably sold 2 or 3 in total compared with 30 or so of the later type.
The good news is that you can use the early type sprocket with the later type sliding member. You will only have half the contact area so it will wear out at least twice as fast but it will work perfectly well until it does wear out. Judging by quite a number of sprockets and sliding members I have seen over the years, use of the narrow contact area sprocket with the wide contact area sliding member has been a common practice in the past.
36 4G, 37 VH, 54 KH(A), 75 Healey 1000/4, 52/53 ex ISDT KHA (project).
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.