No, simply replacing the file is enough. The system will pick up and use the new file as soon as it is in place.

SNFServer will automatically load the new updated rulebase if you copy it to the snf directory while SNFServer.exe is running.  Usually SNF picks up the new file within about a second of seeing it.  SNF will load and check the new rulebase. If there is something wrong with the rulebase file it will keep the current rulebase active until a better one shows up.