Not much to it really.  A big flap controlled by a push pull thing at the dash.  It disasembled pretty easy except for a bracket on the side held on with these rivet type things.  Hmmm, now how was I going to replace those things if I ground them off?  I researched all different kinds of rivets on the Internet and determined that I would NOT be able to use the same style fasteners.  The original type are "stamped" into place with big machines that, without great expense and difficulty, can't be done at home.  The only real alternative (read cheap and easy) was to use your standard pop type rivets.  What made me feel better about using pop rivets was the fact that a certain high dollar heater box restoration service uses pop rivets in their $450 restoration of said box.  If it's good enough for them, then it'll work fine for me.  I did have to dig around for the right diameter and grip pop rivets to use, along with the right washers since I would be connection to the plastic or fiberglass housings.  Anyway, with that dilemma out of the way I ground the heads of the existing rivets off to release the bracket from the housing.  With all the parts separated all that needed to be done was to clean, re-plate and or re-finish the pieces.  This small vent box wasn't too much trouble.  The plastic housing cleaned up beautifully with household cleaners and a toothbrush.  The flap inside had a rubber seal around the edge that luckily was still good so all that was needed here was the metal part beadblasted and a coat of POR15.  The bracket removed from the outside and the rod that opens and closes the flap were electroplated using the Eastwood setup.  All remaining parts were blackened.  Everything went back together quickly once all the parts were dry and ready to handle.  I was genuinely impressed how it looked when finished.  This project was such a breeze I was ready for the mothership of vent boxes... the heater box!