As part of my "winterizing" project on the '72, I decided to finally connect some hoses from the heater plenum up to the two dash-mounted defroster vents. Surprisingly, the one on the driver's side has a round connector on the bottom and the one on the passenger side is NOT. It's more of a perfect oval shape on that side. The vents otherwise look the same....and unfortunately both are equally brittle. I managed to break off all the spring clip retainers after attaching the hoses, so what I'm trying to figure out is what I should be ordering as replacements????