Here is a screen grab of the crankshaft head for a 1976 9.9 of the M E site.
Shows the top one which i would assume is the original 0385971 (1 seal)and the lower one as the
2 seal unit (same as on a ’89 9.9) I think they have their wires crossed and have the parts listed wrong as it says the 0394327 is obsolete, they have 1 in stock ,they have 6 of the 0385971 in stock at a 1/3 the price. if you look at their site for the 1976 9.9 and click on the "more info" on the part, you will see what i am talking about. Somethings weird here or it is too late at night to be doing "research"
"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson