The short answer is yes, but don't. The Raspberry Pi is not designed to run in offline mode since it lacks a Real Time Clock (RTC).
In order for the device to Raspberry Pi to handle time properly, it needs to be able to communicate with an NTP server. If not, it can be off by several years, which of course isn't ideal for a digital signage solution.
As such, you need to either configure the system to connect to a local NTP server, or use some alternative method to set the time (such as htdate).
Alternatively, you can add a Real Time Clock to your Raspberry Pi, but that's beyond the scope of our support.