Old G4 with iTunes - file structure

I've been running iTunes on this machine since 2003. Did iTunes have a different place that it stored backups in the early days? I am looking for a backup for my phone and iPad, and nothing is there, yet I know I've backed them up.

I am currently running iTunes 10 on 10.5.8

I do have the MobileSync\backup folder, but it's empty. When I search for MobileSync, nothing shows up

I have some backups on my laptop so I know what they should look like, I'm just not seeing them on the desktop. My entire music library is on the G4

Thanks,
Diane