Well,
that's obviously not true.
If the Turner "Flying Dutchman" is a different ship altogether, then that completely defeats 100% of the storytelling in At World's End.
So logically they
must be variations of the same ship.
As can be seen on-screen when debris falls off of her bow right before they blow Endeavour to smithereens.
In what way?
And how can you tell?
She shows up in the film for about 2 seconds.
For sure the gunport designs changed to Lion Heads though.
That's below the masts indeed; just as you say.
Only time can possibly tell.
How could anyone show you a screenshot of something that has yet to be made?
That would require a literal time machine.