You're wanting to take the exhaust off the '92 Bonne and put it on the '93 Olds, right?
Not knowing the Olds 88 undercarriage at all, I'd have to say that you need to get a good look at clearances and hanger locations before you go any further. Also, compare the exhaust pipe diameter, which should be the same, I would think.
Other than that, I can't see any reason why this wouldn't work. You are doing this to get the dual exhaust look on your Olds, correct? Is the '92 Bonne a parts car?