The current owners MUST have known the crew failed to get the corresponding licenses. If not, they were quite sloppy in their preparations. Normally, getting a validation for these kind of flights, the "locals" will be helping with all the paperwork and the national licensing department.
And if they DID know, that makes them culpable as well, willingly letting an incomplete licensed crew fly their plane.
I rented planes all over the world, but I never got a simple C172 from the FBO/Club w/o them checking my license..... Plus a checkout of course...