Yes, nvidia-settings -l loads the .nvidia-settings-rc file and applies the settings inside. To query whether sync-to-vblank is enabled, you can run
nvidia-settings -tq SyncToVblank
If it prints 1, it's enabled.
You can use
nvidia-settings --describe list
to get a list of all attributes that can be queried. Use "all" instead of "list" to get a short description along with the names.