Compressed,
If you've got some way of measuring the temperature going in and comming out of the cat converter, it will help tell. Hotter out means it could still be working: Same temp in and out means it's bored out. Saw an infared temperature sensor gun on sale from a company called Harbor Freight that tempted me the other day. That company's great for selling seldom-used odd tools, but we don't help the American economy doing so, I'm afraid to say.

'80 4X4 Longbed