I'll have to dig through my old phone to see if I took pictures, but the bar itself mounts where it needs to, It's just too wide. There are large collars circling the bar where it would meet up with the stock rear bushings on the knuckle for the Monte, if you grind those down or cut a notch in the bushing you can make it work. My car has been using it for years but I don't know if it made a difference. Next time I have the rear wheels off I'll show a picture, but it isn't pretty lol.
Edit: The 1.5 bar really is the exact same shape as the first gen one, you just need the monte carlo bushings. If it was a slight amount narrower it would be a perfect fit.