It very well could be. RX-7's have those, it's basically a thermoswitch attached to the floorpan. When the floor gets to hot, it triggers the light.

Go for a good hard drive, then look under your car. If the cat is glowing, it needs replacement ASAP. If it isn't glowing, you may still want to take it off and have a look inside (when it's cool, of course.)