I have a 68 with factory air. I want to replace a seal that is on the vent "door" that is pnumatically actuated. It is physically located on the passengers side kick panel. The seal appears to be a foam rubber type sandwiched between two plate that are rivited together. Does anyone know anything about this? I have a recycled rubber mate that is the same thickness that I was considering replacing it with. Mistake or not?

 

I'm not sure if that foam rubber type seal was factory installed.
Does it leak at all? water on the floor after a wash or rain?
If it is currently staying dry in that area, I would try that recycled rubber
mate that you found... also, for added insurance, I would put a bead of silicone on both sides
of the rubber before installing.

 

Here are two images that may help.

 

Oh... I misunderstood you.

Yes, if it's in that bad of shape I would try to replace it with your recycled rubber that you have. That door seal is not keeping out water, it's just to keep out air, so if it leaks a bit it's no big deal.