Reading the entire history; rather than just the specs, it does sound confusing. I guess it hinges on the HIN prefix being AJC or WYM.
My '80 is on the cusp and has some features of previous editions and later as well. Perhaps the best advice would be to try to get some local "eyes on" prior to survey?
AFA construction and details; mine is quite sound, except for deck fittings poor installation. From reading recalled conversations posted years ago on the users group, there was some helter-skelter assembly work done on transitional models, especially during ownership/name changes.
I hope it all goes well for you

Regards,
Paul