Mountcastle’s proposal that there is a common cortical algorithm doesn’t mean there are no variations. He knew that. The issue is how much is common in all cortical regions, and how much is different. The evidence suggests that there is a huge amount of commonality.
V1 in primates is “striate” meaning there are extra layers. Other mammals don’t have the extra layers but they still see. The implication is that our vision system has tweaks that improve our vision, but vision in general works on principles shared with other mammals.