RedHat 7.1

I'm using logrotate.d to rotate and process my apache logs. I have 3 logs access, error, mod_gzip. Each of them has a postrotate section that sends a USR1 signal to apache. Is this really necessary? I assume sending the signal once would suffice. Is the file processed in order? Should only the last file send the signal?

Yes, I would say you don't need to restart apache everytime. The logrotate file does execute line by line, so you can just put the command in your last logfile configuration section.

Hope that helps.