Yes, the film is in a normal cassette, but it has no anti-halation backing (that is what gives the “glowing highlights” effect) so if the leader is exposed to any light it transmits it along the length of the film like a fibre optic cable. The film cassette comes in the usual little black plastic container, but can only be taken out of that container in total darkness. Either a darkroom or a changing bag. For this reason you really have to process it yourself unless you can find a lab that knows how to handle it.

That also reminds me, if the camera uses an infrared diode to count the film sprockets rather than a mechanical wheel it will also fog the film to some degree. Most newer film cameras do this although your rangefinder is probably mechanical.