No, you do not need to tick the NTP Setting in the Signagelive settings screen on LG webOS Panels; unless you wish to use your own NTP Server.
You should be aware that Signagelive releases client updates to these devices which is our Media Player software and not to be confused with LG firmware. In Signagelive Client 1.84 (released in 2019) we added an NTP Server setting to our settings screen to ensure that if ticked that customers could use their own NTP servers if they wished to sync the time server with their own NTP.
However, to confirm if you don’t tick that option then the default approach is that the LG Panel will sync directly with Signagelive’s time server - so you can essentially leave this setting alone unless you specifically wish to use a different NTP at any stage. This sync to the Signagelive server will ensure the process of setting the time and ensuring the scheduling and media adheres to the timings you set within the Signagelive HTML5 interface.