rsyslog doesnt seem to write to log file, without restart after touch'ing the file

I have a separate file for logging local7 facility, and this file is touched and _permissions_ set, from my installer. But sometimes I see that the logs are not being written to it (after I do a re-install) until I do rsyslog restart! Is it mandatory to _restart_ rsyslog if the log file is touched by another program/application ? (since the installer is run as root, the log file's time-stamp will be changed due to touch - will this cause rsyslog to not write to the log file ?)