Distribute and upload dependency DARs?

If I have this:

• two Daml projects, app and lib
• the app project depends on the lib project
• the lib-1.0.0.dar contains the org.lib.v1 as the main package
• the app-1.0.0.dar contains the org.app.v1 as the main package

My understanding is that the app-1.0.0.dar also contains the org.lib.v1 package.

My questions are:

1. Must my app’s users upload both DARs to their node? Or is uploading app-1.0.0.dar sufficient?
2. Should I distribute both DARs to my app’s users? Why?