Alternator Question?

That alternator is one from the 80s. The part number is probably 4091424 judging by the fact the housing has thicker fins than the older ones and a ground terminal. The upper spade terminal is not grounded, it is an isolated field alternator. Look closely and you can see the black insulating washers under the screw heads. Chrysler added that ground location around 1978, but they never used it until around 1983. I've never heard any reason why.