You can add a duplicate RefDes to the Silkscreen and Assembly using Add > Text.
1) Add > Text2) Change the Class to REFDES and Subclass to SILKSCREEN_TOP under the Options Tab3) Select the component4) Indicate text location and enter the current RefDes Text.
This text will be associated to the component and move with the component. One word of caution, if you enter a different RefDes than what is current assigned to the component it will rename the RefDes to what you last entered.
I would always change the extra RefDes text to the DISPLAY_TOP subclass so I wouldn't have a duplicate RefDes on the SILKSCREEN_TOP subclass. Just make sure to include the DISPLAY_TOP subclass with your silkscreen artwork film record.
I guess another alternative would be to update your library symbols with a RefDes place holder on the DISPLAY_TOP subclass and refresh the symbols using Place > Update Symbols.
Hope this helps,Mike CatrambonePlexus Engineering Solutions