OK Phil, i figured it all out for you. all you will need to use from the Dewgong is the actual airbag charge. everything else will be used from the 2002.
take the 2002 airbag and turn it upside down like so...
using a 10MM wrench or socket, remove the four bolts on the rear of the airbag
upon removing them, slide off the bracket on the back.
take off the main metal rear of the airbag. this holds the charge in place.
after doing this, you will notice the 2 stage charge of the 2002 airbag can now be readily removed.
2 stage charge removed.
airbag shell with cover still on is whats left.
now you are ready to follow the same steps disassembling your 2000's airbag, and put the charge from your 2000's airbag into the 2002 airbag shell, than bolt it all back together.
you now have a hybrid 2000-2002 airbag, complete with Mercury Logo! and instillation will be 100% plug and play.