Sketchup.active_model.path returns the full path to the SKP.
and Time.now returns the time/date.
To get the user try ENV["USERNAME"]
C:\Users\TIG\Desktop\oxo.skp Tue Apr 02 15:50:39 +0100 2013 TIG
You can tailor the 'date' by using things like:
"#{Time.now.year}-#{Time.now.month}-#{Time.now.day}"giving 2013-4-2
It'd be straight forward to add some screen-text that included these text strings.
Updating it could be done with an onStart observer ?