Answer
Yes, you can. However, if you disable it, then none of the standard reports will display the name of the local time zone.
To disable local time display in IGSS standard reports, go into the Windows registry and find the key:
HKEY_CURRENT_USER\Software\7-Technologies\IGSS32\7.00.00\Report_HKLM\ShowTimeZoneText
and click on ShowTimeZoneText and change the number in the Value data: box from 1 to 0. This disables the display of local time in all standard reports.