The dealer may or may not be totally honest with you. To determine if they're pulling your chain, first reset the light. You can do this by disconnecting the battery for about 5 minutes then reconnecting it (disconnect the negative lead by the way, that way you don't have sparks flying if the postive lead touches the frame or engine). Make sure you have the code to your stereo if you do this (if you have a crappy honda factory stereo) as it will reset the stereo as well and you'll have to enter the code to make the stereo work again. After reconnecting the battery turn the car on and see if the light comes on. It might come on immediately or after a while. If it doesn't come back on then it may have just been a glitch. If it does come back on, take it to an autozone and get them to read the code. They might be able to tell you what the code means, if not, google it or post it up here. If it turns out to be the catalytic converter after all then I'd recommend you replace it yourself. You can get a new CC online for between $150-$200 and replacing is not very difficult for even a novice DIYer.

If you're not much of a Do-it-yourself kind of guy then you can opt to have another shop give you a quote or have the dealer do it since they will offer a warranty. I personally would get a quote from a shop, they may be able to get the part cheaper. Shop around for a catalytic converter and if you can get it cheaper, buy the part yourself and then have a shop simply do the labor and put it on.

But as I said before, just do it yourself if you're at all mechanically inclined. Get a Haynes, Chiltons, or preferably a Helms manual which will guide your through the steps. It's quite easy. It's just forking out the couple of hundred bucks to buy the converter. Still better than the thousand bucks the stealership wants to charge you.