I was thinking the wrong thing. My mind was on the black plastic housing. I believe it's round. I didn't read your question very good. I'm really not sure about the terminals for the later years.
Every Maverick I've had was a flat blade. I did the tech article on the intermittent wiper swap and sold about 30 conversion "kits" for the swap - all were sold here and on ebay and nobody ever complained about fit issues. The only difference that I know of, is when the wiper knobs changed from early to late style, the flat spot on the switches mounting shaft was rotated 180 degrees. Which can cause the printing on the wiper knob to be upside down if a later switch is used with and early knob - an easy fix.