Well, i don't see so many differences on the machines.
We have som small changes because of special safety rules, but the other ones is because dirt is not always dirt.
And the use in Europe may be in another way than by u.
A excavator in Norway is mostly used for loading rock, thats way u will see that our buckets is shaped differently than yours. Loading big rocks with buckets like the ones u got is very difficult, so we use the ones with a longer tounge sticking out in front bottom.
Is a picture here:
https://www.heavyequipmentforums.com/Forum/showthread.php?t=3340
Other changes goes on that we use the same machine for a lot of things when u are at the site.
You then got rotator, angle, quick coupler, forks(yeah forks for the exc), trailer, different buckets, and so on.
A wheel exc working on road construction is often the one with most addons.
But the base machine is the same as you got.
(our drivers demands the best, so u dont find any without a cab and ac..)
Some types is exactly identical. ADT, dozers and wheel loaders for example.
Difference may occour because of operatordemands, type of work or safety.