Mine is a 2007 and has the fake nuts. I used a pair of water pumps and tried wiggling the nut. The fake one will give a little and then just pull off exposing the lock nut.
So one of the 8 fake nuts needs to be removed to access a hidden lock nut? All these years on the PC forum and I never read that before. I learn something new all the time.
I think Joe R may have followed the same (WRONG) path I did when first removing my wheel covers.
I have a 2006 2350 with the Wheelmaster Wheel covers. Each cover is held on by (4) retaining or 'fake' lugnuts. These are a chrome cover over a nut that threads onto the bit of stud left exposed after the wheel retention lug nuts are installed.
Still available new -
https://www.etrailer.com/Wheel-Accessories/Wheel-Masters/WM168E0JC.htmlThe hard (wrong...) way to remove the retainer nuts is to pry off the cover, using pump pliers, exposing the nut. then use a socket to remove nut. Then the lock nut covers dont install tight at all...

Yeah, took me a wheel to figure it out...

The EASY (right) way is to look at the lug nuts on the wheel cover. You will see that (4) of them have dimples at the bottom. Using the 'T' handle tool (found mine in back..) easily twist off the (4) locking nuts to remove wheel cover.

That easy. If the t-handle is missing, a regular socket will remove the locking nuts. They are easier to re-attach with the T-handle, as it allows you to easily push in on the cover to allow the nuts to thread on.
As a side note, when I replaced my front rotors (discs) on the E350 doing a front brake job, the studs were just too short to engage the retainer nuts. I had to machine ~60 thousands (.060 inch) from the wheel retainer nuts to reattach the covers. They have worked fine ever since.

Shown below are the wheel covers found on my coach. In one pic it is easy to see how (4) lugs hold the cover on. The other pic shows all the locking lug nuts that come with a set, and the tool to remove them.