The owner'* manual will talk about it whether your car is equipped with it or not, as it was an option on several syles of H bodies. I don't see an RPO code in Techinfo for this. I didn't even know I had the option until I had my windshield replaced. It made a very expensive HUD windshield a bit more expensive, and the order took a little longer to fill. Thankfully, this forced the insurance to pay for an OEM windshield.
With a quick glance, I don't see it even mentioned in the 93 owner'* manual. I'll have to dig through it more carefully. I can't see the heater elements in the glass with the windshield installed. They're below the line of sight. I can tell you that it works pretty well. I'm usually the first one out of the parking lot at work in foul weather, while everyone else is scraping. My mirrors, winshield, and rear window take care of themselves.
It can turn this:
In under 5 minutes. It doesn't totally melt the ice/snow if it'* thick, but it frees it from the windshield so it can be pushed off in an entire sheet. It DOESN'T thaw the ice dam over the wipers very well. I lost a wiper yesterday, and had to replace it.