85hp 1993 year. lower unit application

Thought I was getting a 90 hp turns out it is a 85 HP 1993 year.
Dealer says no other lower units will work. Just the specific unit for the 85 hp motor for those 2 years.

I am under the impression that most 3 cyl. 2 stroke motors have interchangeable lower units.
Please help me get this right, as I am getting a good deal only if the other lower units will fit this 2 year production model.

Thanks,
John

[boats.net]

The lower unit part number for the 90's are different than the 1993 C85. The 1992-1994 C85 lower unit's are interchangeable. The Remanufacture catalogs list them the same lower unit.