Well, looks like I won't be obtaining a Johnson MC97 impeller for our engines Oberdorfer 202M-series pump. Johnson doesn't make one for that pump. Nor does Jabsco. The only impeller manufacturers that make impellers for our pump is Oberdorfer (Neoprene), Globe (out of the question), Barco (whomever that is--same p/n as Globe, so I suspect that's a re-badged Globe) and Sherwood (which I cannot confirm because their web site is basically utterly and completely worthless.)
So it looks like it's the Oberforfer impeller for us.