How many miles do you have on your 97? I threw a check engine light last year and took it into the dealer. They gave me the same diagnosis and of course wished to sodomize me with two new cat banks. The problem was the 02 sensors.
I found direct OEM (Bosch) 02 sensors, replaced them, and have not had a issue since. 02 sensors are often overlooked as maintenance items. I stress they are something that need to be changed. My 97 Arctic had 79K on it when I changed them.
Food for thought.
One other thing. The cat problem is apparent with these vehicles. The previous owner of my vehicle had both cat's replaced with MAGNAFLOW Catalytic Converters. They are high-flow, and a fraction of the price. Again, no issues at all with these.
I understand and appreciate sticking to OEM parts. But I also think that there comes a point when something works just as well and is 80% less cost to do, then it should be entertained at least.
Good luck either way.