They always tell you it's a M22 when they own it or use to own it.
It's like every old Mustang with a 302 in it is a Boss. If you see enough of them you can tell what it is by looking at it. They only used the fine spline Muncie for a few years and then it was replaced by a BW Super T10. There are websites that can tell you the ring count on the input shaft. The input shafts can be from a different transmission if someone worked on it but chances are it's what came on the transmission.