I forgot about the spacers...... It's my age! The Shim inside the carrier is common to all Renault models, as is the o rings on the sunwheels, after a certain date. This mod was added to try to stop wicking of oil up the splines causing nasty little oil leaks that cannot be cured. It is a sort of phase 1 output, to phase 2 output improvement. The final incarnation was a much longer Sunwheel and completely different sealing arrangements which do not interchange This is on the very last 1980's 3 number series boxes and the NG series (except the NG5 as it's Renaut)
The spacers carry the camber thrust load from the u/j to the carrier or crownwheel , depending on side. I am guessing they did this rather than make the inner u/j the correct length, as this was a tall order and would not make parts interchangeable if Renault changed the Spec (which they do often)
The only other Europa oddity I have uncovered, and this is a Theory not a Fact, is that on the Lotus version of the 365 (early 12G type) the first 4 gears are as per Renault, but with a standard 0.86 5th. The thing is at the time this happened, the 0.86 5th wasn't standard, it was a special. This may be why the boxes I have done had Hewland Manufacture 5th gears with the flying H on them, but were otherwise Renault.
I never understood why they went with 4 close gears, then a big jump to 5th in the Europa, but figure it was for a claimed top speed or economy reason. At this time Renault were using 0.93 in the 12G box and 0.91 in the R16 box. After about 1972, the 0.86 becomes the Standard Renault 5th ratio and is found in everything.
I always find production modifications very interesting as they usually allow the early system to be changed to the later system without modifications when replacement time comes along. I know we generally curse car designers, but often they do come up with some very clever adaptations of their own designs.