Stocking up on parts before a repaint --

Questions:
1) what is the part number for the plastic piece around / behind the gas cap? Can't find it on vendor sites.
2) will the late seal for the sliding door handle work on the early door? Old one appears to be NLA.
3) I know the late rear windows (with flow-through vents) will install into the earlier van. Is there a seal or anything between the glass and the plastic vent? Or is it just glued?
4) does anyone carry the stock-style basket weave vinyl (used on shelves, ceiling, etc...) besides Go Westy?

Lastly, I'm looking for a pair of tan/brown curtain sliders (same style as the late Westy) to install while things are apart. Anyone have 'em?

thanks,

john