Exhaust pipe noisy

Greetings from Jämsä! Now that summer has come again, it's time to do some repairs on my RR p38 Gems -97 car. There are a few tasks on the list: Door lock, odometer reading, flap housing adjustment, cruise control operation, rear door inner handle, etc.
First of all, I would like to ask about the catalytic converters: I have listened with a stethoscope that the right-hand catalytic converter makes quite a lot of noise, which can be heard from under the car. The noise quiets down when the piping warms up. There is something loose in it. Now I would like to know if there is any information about which catalytic converter would fit my car, whose TA serial number is 95-97. I have a total of 2 lambdas. Euro2 is apparently the correct emission requirement. There is a wide range of options on the internet, both in terms of price and models...

Addition to the previous one: The catalytic converter has the identification ESR2580, which I can only find on some old ones that have been cut off.

it is possible for the material inside a catalytic converter to crack/break apart and cause a rattle. this can happen if the exhaust is very hot and you drive through water, the sudden cold shock can damage it. in theory

I haven't driven into the water in the way mentioned. I don't know about the previous ones. They have a stamp 2 96 which could be the date of manufacture?
They may have been damaged during this time. The noise is a kind of rattling, as if a metal plate is loose. With a stethoscope, it is heard most loudly from the catalytic converter. Not at all from the engine or gearbox. Heat shields do not cause that noise.
Now if only I knew which ESR number replaces the original.