Three questions on this:

I have some leftover Thermo Tec. Has anyone seen any benefit in applying this to the door?

The openings in the door were each covered with homemade plastic covers that I made 20-30 years ago out of 5 mil Mylar, but I don't remember if I was replacing factory-original covers.  Were these original?

The entire door was covered by a 'watershield', but I remember even less about that.  The FSM only mentions that it exists, but doesn't illustrate it.  I think it was a thin plastic sheet secured on the top and sides (but not bottom).  Does that sound right?

Thanks in advance...

Here's a picture of the original vapor barrier on my 7/70 240Z, before I disassembled the door. It was held on with adhesive all the way around the perimeter. I assume 280's were similar.