I know that with Mavericks and iOS 7, iCloud syncs text shortcuts automatically across devices. Does iCloud also sync custom Application specific Shortcuts across Macs?
Application specific shortcuts:
No, App Shortcuts are not synced over iCloud.
The shortcuts are stored in ~/Library/Preferences/.GlobalPreferences, so if you want to sync them you are free to symlink this through Mobile Documents, however that file contains many preferences outside of just your app shortcuts.