No, MOMO wheels don't fit directly on the SAAS boss kit. When I was changing over from a SAAS wheel to an Isotta (who make wheels for MOMO, and whose wheels use a MOMO boss kit) I placed the Isotta wheel over the SAAS boss kit, and the holes in the wheel are a little further out than on the SAAS boss. I suppose you could drill/file out the holes in the wheel to make it fit. At least both use 6 bolts to hold the wheel on.
By the way, I always found the SAAS wheel/boss combo to be too close to the indicator, but maybe that was because the wheel itself was flat not dished..?