Are injector crush washers actually universal, or do different applications require specific washers even when using the same injector?

[Ellen Deuch]

I'm working on an EC210CL injector setup and noticed the injectors are used across multiple applications. That got me wondering if the copper crush washer that comes with the injector is truly universal, or if different engines require different thicknesses, sealing washers, or injector seat specs. I've seen a few forum posts where using the wrong injector washer caused sealing issues, injector depth problems, and compression leaks, even though the injector itself was correct. Just trying to avoid installing the wrong parts before everything goes back together. Curious what others have run into with injector crush washers, copper sealing washers, and diesel injector applications.