but yes, now that I read the documentation, 3.5 docs it say very explicitly that:

  Two aspects are guaranteed not to change:

    - If a new seeding method is added, then a backward compatible seeder will be offered.
    - The generator’s random() method will continue to produce the same sequence when the compatible seeder is given the same seed.

thus no guarantee is given about any other method at all, including randrange and randint.