User can use 2025 cloud models and links, but not 2024, despite Addins folders all being empty!

One of my users just opened a 2024 cloud model, and when trying to update the links (also cloud models in the same project), it said he couldn't because the Autodesk Docs (or maybe Collaborate?) addin was not installed. But all of our 2025 projects work fine, all links load and work correctly. But when I went to look at ProgramData > Autodesk > Revit > Addins, it listed the year version folders, and they are ALL empty! So:

1. How could the 2025 models have working 2025 cloud model links on their machine, and
2. What is the proper way to get the .addin files reinstalled? I checked Program Files > Autodesk > Cloud Models for Revit 20xx, and all those Collaborate.dll, CollaborateDB.dll and other DLL files are all there. Can I just copy over the .addin files from another machine, or is there a more "correct" way?