Time series on syslogs
No, according to your description the syslog is not a time series data.

Time series data means to have a numerical value at each time stamps. For instance, if your log records the CPU usage (a number between 0 to 100%) then it is a time series data.

If you log is a sequence of text message, like the /var/log/syslog in Linux, then it is not a time series data.