A/C Box door seals help

I have called all around and can not find this seal. I am tempted to get the one from Docrebuild but with having to mail payment than wait for the part and needing it soon to continue on with my project I am not sure. Plus and this is the part that worries me is that the pin is pressed in to the door and I am worried about damaging the fiberglass heater box if I remove it. It seems to be stuck.
I was thinking about just making a seal. Anyone have any suggestions on the best material to use. I think just a sheet of ¼ rubber will work but want to get something that will not deteriorate.
At my local grocery store, usually red, but I've seen other brands in blue. If GM would have used this material originally, it would still be in new shape.







