Depends on your intentions.
The Moment was one thing - that's vanilla Android.
If you're wanting to just play with files already on the card on the Epic - would probably work.
If you're wanting to run everything normally - maybe dbpaddler would know - if TouchWiz is requiring any special folders to work - or - if they have any Linux-extended filesystems pre-installed on the Epic, it'll be sadness for sure unless you use the phone's built-in format tool to wipe and re-do the layout on the SD card.
Please tell me you're not swapping the 16 GB for the 2 GB between the two to sell the Epic - at least tell the buyer what he's getting.
I don't want to give the impression of hidden as in top-secret or anything - just hidden folders (names preceded with a dot). This is a _very_ common practice on unix-based systems.
These sorts of folders seem to have some handy stuff in them and are used by HTC Footprints, Bookmarks, HTC News, the HTC Mail app - that sort of thing.