I thought I had seen that in the past, but today I only have the video window. However, the Mac is a MacBook Air with an external monitor and the clamshell closed; would that make a difference? (And if so, why? It still rings when someone calls.)
[Edit. I did see a Recents sidebar when using the MacBook Air without an external monitor.]
Also, the Clear All Recents command is gray, so maybe FaceTime believes there are no recent calls, and that’s why I don’t have the sidebar. (There are recent calls, and I didn’t clear them, but I recognize that cosmic rays do strange things.)
It does seem like a strange omission that I cannot tell which identifier received a call.