Correct. Vertebrobasilar-source embolism would cause acute transient BINOCULAR visual loss, a contralateral homonymous hemianopia. This patient is reporting MONOCULAR vision loss. However, be advised that many patients mistakenly report monocular temporal vision loss when they have actually suffered transient homonymous hemianopia! Think of the anterior arterial circulation for MONOCULAR visual loss and the posterior arterial circulation for BINOCULAR visual loss.