yes you do and a great opportunity to replace all the rotten foam rubber that hinders good seal and separation between defrost and floor setting as well as opportunity to lube up your heater setting cables. Also to clean your vent boxes and gain good access to cleaning your fresh air chamber. often filled with debris, pine needles leaves, and such. It's a couple hour job, but you will be glad once you complete the job. Just did mine on my 68' during my dash resto.