If you have a template for your part files and you add this into a note it will insert the mass of your whatever part you insert as the first view.
"SW-Mass@$PRPSHEET:"SW-File Name".SLDPRT"
if you have a template for your assembly files add this note
"SW-Mass@$PRPSHEET:"SW-File Name".SLDASM"
Regards Corey Scheich