There were far more 1986-1991 126 Gen II & Gen III vehicles sold in the US than the 1979-1985 126 Gen I vehicles - 343K vs. 278K

Considering the attrition rate over those years I suspect Gen II & Gen III carcasses would be more prevalent still today and therefore more available. It probably might makes more sense to find and make use of parts from the same generation vehicle than to try and make parts that are close but not exactly the same work from a time/cost perspective.

Here on the east coast late 126 cars are still pretty plentiful in the boneyards I frequent, earlier 1980's models are less frequent for sure.

You might check around at the various towing companies in your area, lot's of times they tow junks for scrapping they will sell for the scrape price. Might make a difference where you are located in NE?