I did not see this here, so I'll mention it.
Take the vehicle VIN to the local BMW dealer and ask them to run it. They may charge for an hour of labor, or do it free...
That will tell you
all dealer performed service an maintenance since the car was sold new. If this wasn't serviced at the dealer, you are SOL unless the seller has a pile of receipts.
In that report, you want to see things like "
service II" which (back then) included brake fluid flush and other items not done any longer, because all of a sudden, these fluids started lasting
forever and never need changing.