Have a look for this:
It's down by the starter motor.
And M52's never came Alusil lined either.
Also, if the engine has been changed the official way, then you won't be able to see it from the logbook, as the engine numbers should match up.
The best way to find out if the engine has been changed by BMW is to ask them - When I did, all they could tell me was the short block had been done, but they didn't know when or why. The age of the car would suggest it was because of Nikasil problems though.
As for 100ml a month, depending on mileage covered, I really wouldn't be concerned by that at all !