The Wildcat Mustang and Mercury Cougar almost seem related in the Lesney scheme of things, they both have identical 'engine well' castings, share the same engine and the label from the latter appears on the former, as in your model.
I wonder how easy it is to remove the labels without damaging them, as this could lead to label 'reassignments' to turn a common model into a sought-after variant. Interesting stuff, maybe worth starting a thread on!

Cheers, Ken