To topic's question: No. Ovi doesn't need 8th Rocket to cement himself the GOAT goals scorer. Few hundred goals from top 10 goal scoring seasons would be enough.
Rockets and pre-trophy goal scoring wins are funny thing, they adjust themselves automatically to their goal scoring era of making, being always absolute to their corresponding season. Relative comparisons between seasons are meaningless when counting amount of Rockets won. Winner(s) scored always most. Most important here in this evaluation isn't only the total amount of goals the winner managed to put in, but a difference to 2nd best of each season.
When Bobby Hull played, NHL was little more than Elite beer league when counting participating teams in it. Less players to compete with. Different amount of games per season. Different rules. etc.
Ovi's 7 Rockets are the result of harder goal scoring era than any other multi-rocket / goal scoring winning assortment of anybody else. Someone can count differences of differentials between the 1st and 2nd scorer (I know that someone has done that already, but can't find/too lazy to find it now).