Wha?!
The lower crown has the steerer tube attached to it, so your question doesn't make sense..
You may want to check out how the forks are assembled, or rephrase your question as I'm unsure you know what you're particularly after. But to answer what I think your question is, you can run a top drop crown with the "flat" lower crown (though I doubt Marzocchi made different ones anyway).
Cheers,
Theo