The color change you're seeing is a function of both the RadioReference database and the programming which creates what you see on your web browser. When you bring up a certain section of the database on your browser, the programming looks at the "last updated" field for each record; if that date is within the last 24 hours it causes that record to be displayed in green. Likewise, the following two to seven days are then displayed yellow. After one week, the record reverts to normal display.
You might be able to cause the same behavior to occur automatically in Excel or another spreadsheet program by using a script, but since the "last updated" field isn't available as part of the file download you would have to create and update a "last updated" field manually.