This could be a 509, 510, 511 or 512. The serial number plate is on the bottom side of the fan casing.
Nice find, and the bag is really rare. Whatever you do to it, I'd treat it very very carefully. I'm not even sure that, were it me, I'd even risk removing it from the sani-emptor. Sometimes when doing so with old bags, the spring inside is rusty and snaps apart when you pull on it, and/or the fabric of the bag could be brittle and the bottom will tear.