No, the serial ports are not reset. Mac OS 8.5, 8.5.1 and 8.6 include Chooser version 7.6.2. It is true that you will hear a System beep upon opening the Chooser with the Option and Command keys down, however, there are no parameters that are automatically reset. To reset serial ports on computers that have them, you will still need to reset the parameter memory (PRAM), by restarting the computer and holding down the Option, Command, 'P' and 'R' keys. For more information on resetting PRAM and NVRAM, please see the following Knowledge Base article:
Article 2238: "
Macintosh: How to Reset PRAM and NVRAM."