Going by the chart I would agree with you except my serial numbers are all calling it a 1971 m20, I ran tail stock number, trans number and date code all pointing to m20, again from what I've reaserched the muncies whent too three bolt holes instead of 5 part way through 1970 I believe. Which makes sense since yours is an earlier 1970 tranny it would fall under the older generation. Even my tail stock number falls under a m20