Unless someone went through the trouble of importing one, there are no Stradales in the US. A true MC Stradale was a stripped down (i.e. leaner, more powerful) offering with no rear seats offered only in Europe.
What you are seeing with the side vents, hood and center exhaust is the MC trim, which was a more expensive option compared to the standard Sport trim.
There are way too many inaccurate listings when it comes to the GT. If you are looking for the MC then the dead giveaway is the center exhaust, side vents and the hood. If the listing doesn't have any pictures, use the Maserati's Recall check tool to check the VIN number. It will correctly identify the car as Sport, MC, Vert, etc.
Recall check on your Maserati - Search by VIN | Maserati USA
Lastly, note that Maserati offered a "Sportline" package that could be added to the standard Sport trim. From what I recall, Evolution I was an exterior CF package that included mirror covers, door handles, trunk lid. Evolution II was an interior CF package that includedgauge cover (gauge is also black and says MC instead of the standard blue), door and dash trim, shift pedals, steering wheel, brake/gas pedals, shifter, etc.
Also, the Evolution I and II packages were not completely standard for the MC. There were some CF items theat were included while others were options. The Skyhook suspension was also an option. So it really was possible to have a one off MC depending on what the original buyer wanted.
Hope this helps.