dust cover, 340/727

Need help, bolted up the transmission and need to but on the dust cover (1) does the dust cover go between the bellhousing and starter? (2) I have seen dust covers that are flat across the top and others which have a hole for the starter, which one is correct? (3) In the event I don't have the right dust cover, is it advisable to go ahead and mount the starter (I'm putting the engine and trans. in as a unit, with headers)