but, if the phone has the DATA radio turned off for a while and the battery removed during that time, the clock will be wrong.
and also IF somehow the phone's Date/Time clock has been reset to a different date and/or Time Zone, then the answer is YES. (but this will automatically correct itself IF the proper settings is clicked to "Automatically Update Time from the Server") the wording is different on phone models, but the meaning is the same. You can force the phone to any Date/Time you wish by simply turning off the Automatic Date/Time Server option... as long as that is unchecked, the phone's internal clock will simply count time.... it is totally unaware of Real Time until you Click the Auto Update box. then it will correct very quickly.