After some googling, did manage to find the original Apple user-manual for QuickTake 150 for Macintosh. It doesn't appear on Apple's site for some reason, only the Windows version of the user manual is present.

Haven't got the serial cable as of yet, so can't see the files. Anyway, the camera is amazingly clean, no scratches, no battery leaks (had batteries from 2005 inside) and seems to have 9 pictures already been shot with it before. The strap would be nice as well other accesories for it.