Do I need ntpd on a LAMP server?

A typical single LAMP doesn't usually need a full-blown NTP server - to keep your time accurate add a ntpd -q job to run every day.

You need an NTP server when more accurate time synchronization is required (like in a case of cloud-based service, distributed along a number of instances) or when your software have issues with jumping clocks (since ntpdate (which actually is deprecated in favor of ntpd -q) will directly set the time instead of slowly adjusting it).

If you choose to run ntpd, make sure you add a firewall rule to block incoming connections, since it is a widely-known target for NTP Amplification DDoS attack - having it open to the wild will cause high traffic usage and abuse letters to your hosting company. Run ntpd -q once at startup before starting ntpd to get the benefits of the better tool.