1971 vs 1972- later sterndrive?

[matt167]

Got a '71 Starcraft Offshore V 18 with Mercruiser 120hp and just wondering what the difference in drives are, should the lower unit ever need replaced. I know SEI says 1973 and later in order description, but then shows 1972 in the application list... Will an SEI 106 or any later drive work? I know there are differences in the yoke end at the gimball housing between the early MC-1 and the Alpha One gen 1 generation