I've determined that, with the M0001W model number, and the ability to use 800k disks, this 512 had the Macintosh Plus Disk Drive Kit installed at some point. Add in the external drive and the bag, and this thing had a fair amount of dough spent on it. Not bad for free! (It was free to my dad as well; some years ago he spotted it collecting dust at a church, asked about it, and it was his.) I wish it had the original disks in the bag, but no such luck.