Is Universalism Marcionist?

Recently I've been interested in the historic heresy of Marcion of Sinope, who professed the belief that the God who created the world and instituted the Law is not the same as the Fatherly God who sent Jesus down to save souls.

And I think that's a pretty unpopular belief these days. But it sounds a bit like a pathway to universalism; the God of the Old Testament who imposes strict laws, but a path out. How do Universalist Christians square a continuing belief in the Old Testament and its legalism with the claim that God has left all that behind?