Most actual 'user manuals' specific to a build model/year will mention
the Hardware & original 'shipped' version Mac OS X for models that old.
To look for Missing Manuals of suitable macOS or OS X may be an idea.
Mine of older mac systems were found @ bargain prices in used bins.
A few years older than present, those where available in used books, can
be a great deal. I've several for reference. No point to in have 'online book'
or a manual, if the mac cannot see the internet due to some failure.
A second-edition book for the MacBook (white) I bought five years ago
for 35¢ in charity thrift store. It shows old first-edition MacBook1.1, too.
But does not show how to use later software; only Basics, good for now.
{..To think someone paid $25 USD for this, (wiley pub.) I feel better. Since
I didn't need it; & consider to include book with old MacBook, on resale..}
When you live with a marginal power grid most years, a Book can be best.
And you can read it with no electricity, too. A candle does nicely. 😊