I didn't have any issues removing mine, but its not that old, only a '98.
There were 4 (I think) bolts holding it to the swim platform and two to the transom.
They had a sealant around the actual exhaust ports, so I had to wiggle and pull on it a bit, which had me nervous, but it finally came off.
I cleaned up the excess, put on some rubber flaps and away I went.
That coupled with the Stainless Marine exhaust really opened up the rumble.