Place a Callout at the location on the Draft where you want the weight displayed. (the Callout arrow can be turned on or off). Right-click and go the properties of the Callout. On the Callout properties dialogue window, select the Property Text button. Select the Index Reference radio button and in the list of available properites select Mass. Once Mass is chosen, hit the Select button. You should see an equation show up in the Property Text field on the Select Property Text dialogue window. Once complete, select the OK button.
You should be back at the Callout properties dialogue window & select the OK button. You should now be back at your Draft file and the Callout should display the weight (mass) of the first model placed on the Draft file.