My GH1 shoots 24p and wraps in 60i. In the neoscene pref panel I click convert to 24, should I also be checking or unchecking the source is progressive box?

You want convert to 24, the progressive flag is redundant in this case as 24 is always progressive. That checkbox is for 1080p30 sources with maybe encoded at 60i.

I was always under the impression that when converting a 24p file that is wrapped in 60i, we check the "Remove 3-2 Pulldown" option in the Cineform preferences.

I was tlaking about the progressive check box. Yes convert to 24p is for removing pulldown.