Yes, you should have a slight gap. And this will quite often cause "chirping" (or rattling from the dust cover) as the clutch fork bounces back & forth across the gap you've left. People will often needlessly replace throwout bearings when this happens. You correctly diagnosed that the clutch mechanism does not have any way to keep the throwout bearing / fork from moving back against the pressure plate fingers, causing the chirp, when you've left the gap.
So what did Ford do with the stock adjuster mechanism? They left the throwout bearing in constant, slight pre-load with the pressure plate fingers. This will get rid of the chirping, but will make your throwout bearing last about 40k if you're lucky.
Your options are to do what Ford did (remove the gap and tighten it up to the pressure plate), or to add a spring to keep the clutch fork / throwout bearing away from the pressure plate to get rid of the chirping. In my opinion, the kit below (should work with any T5) should be shipped with every aftermarket quadrant setup. A very cheap and effective way to get rid of the chirp (and the "dead spot" on top of the clutch pedal movement which lets it bounce when you hit bumps). I've had one for about 2 years now, and it works perfectly. To me, it's cheap insurance that my throwout bearing won't wear out much more quickly than the clutch, as I'm not a big fan of dropping transmissions. LDC Chicago Clutch Freeplay Correction Kit [LDC-FREEPLAY] : Lethal Performance, Performance parts for Ford Mustangs