Wasn't the Wiki in the v1.3 CVS. I just uploaded and installed a fresh v1.3 script with fresh database and did not see it in the Course Activities dropdown.
I don't believe it was intended to be part of 1.3, no.
For now, it will remain as a module add-on, that you can get from here or from contrib CVS (preferred).
Nice to have it as a modul, thanks.
Actually, Michael's done more of the 'tough' work on this module, and deserves more credit. He's got his hands very dirty in the depths of the erfurtwiki code.