Hi Johan,
There is no direct way to see this information but here are some comments.
The netlist file (.ewnet) is created when you transfer the design from Multisim to Ultiboard and when you Forward/Back Annotate changes; the default name for this file contains the timestamp.
If you make changes to the netlist or the design in general they are saved in the project file (*.ewprj).
Regards,
Fernando D.
National Instruments