Date code and engine numbers that are close are not as important as an original rego or ordering documents with the actual engine number on them to go with the correct engine. That is what lifts a car up above all the rest, along with a documented resto.

All the rest are great to but are not up there with one with proof of originality.

Factory air is a great thing to put in even if hardly any of them got it. Pointless building a van/ute and having no fun driving it in summer.