You have to pull the tail lamp assy. Best if you look at the FSM, but here goes from memory.
Open the hatch. Remove the plastic rear cover (this will involve pulling up the carpet, possibly even removing the floor panels in the rear). Wangle the plastic piece out of there, and try not to break it.
You will see a number of screws that hold the entire assy in. Remove them.
While holding the assy in place with your knee, remove the bulbs/connectors from the assy.
Pull assy away from car.
Lay flat on a piece of cardboard. You will see some more screws that hold the trim pieces on. Remove them. Trim will seperate.
Man, that seems like a lot of work for a little chrome peice. Thanks for your input. I had better order the FSM before I attempt this-also, I think I will price the parts in other channels before going to the junkyard-do you know what that peice is called (in case I have to order one)?
It is a piece of cake. Shoot me email and I send scans to you with the half of page with the 3 drawings from my 77 FSM. You might want to get new revits (8) if you can find them. Or use a solid copper wire and paint them black to hold in the old rivets when you remove them...
When you change the tail light trim rings, be sure to go to the hardware store and buy stainless steel screws to use when you replace them. With Z cars, there is a big problem with backdraft drawing exhaust gases up around the tail light panels, and its corrodes the screws. Had to use needle nose pliers to remove some of my screws. Plan on at least a full afternoon to get every thing out, cleaned and replaced. Good luck.