Regarding the Good Will-Darby PA rig being the final, I do believe this is correct but I seriously doubt it was a 1981 model year as Hamerly closed their doors in April of 1980 according to the bankruptcy paperwork. It may have been made in 1979 and titled/delivered as a 1980 but no way as a 1981.
This was the case with anything listed as a 1980 made by them.
Just my two cents
This was the case with anything listed as a 1980 made by them.
Just my two cents