I believe it's a GL but it doesn't indicate anywhere.

I'm in California and it failed the NO (PPM)
15 mph -- Max 750, Ave 374, measured 758 = Pass
25 mph -- Max 511, have 294, measured 872 = Fail

Would a new aftermarket Cadillac converter most likely make it pass? Also I know there's holes in the muffler and tailpipe. Would repairing those make much difference?

Changed the oil and drove through a tank of premium gas. I don't think the car needs a tuneup.

Thank you in advance for any advice.