In mice, patella would form, but not separate from femur.
On the development of the patella:
Previous studies have suggested a central role for mechanical load in
the initiation of sesamoid development.
Our finding that the patella initially forms as part of the femur and
is later separated by joint formation led us to revisit the issue of
I think the image you've attached lacks clarity. If you see the image below, you could say that the epithelium is cuboidal with central rounded nucleus.
Unlike the oval nuclei of columnar epithelium, rounded nucleus suggests that they are cuboidal in shape.
The image is from https://webpath.med.utah.edu/HISTHTML/NORMAL/NORM010.html