No, the port sequence and spacing is different.
Your heads and manifolds are like this:
(exhaust,intake,exhaust,intake,exhaust,intake, left to right).
Series 1 has the same sequence as the Buick Grand National (and all earlier 3800'* before 96):
So if you look at the Series 1 exhaust runners as they exit the head, there'* a smaller gap on the front bank between runner 1 and 3 than there is for 3 to 5. They won't even bolt up to your car.
It would probably be cheaper to modify the S1 manifolds to fit your car than it would be for headers, but PEM'* made for your car would be cheaper.
Here'* a pic of Series 1 manifolds to show the uneven port spacing: