Well, then you wouldn't have a key fob, would you? Key fob for disarming and unlocking doors is, at least on the factory side of things, directly linked to the "alarm". It's not an alarm in the traditional sense, doesn't beep and whoop when bumped, or if the door is opened without disarming. Seems to only alarm if it senses "forced entry" (I haven't seen any definition of that though).

The route I'd take is to visit a dealer with the VIN and ask them. Most are clueless though, so don't really expect any help there. I'd then try to put the vehicle into programming mode ~ if you get into that you at least know you have One of the systems. There's supposed to be a visual indicator under the hood, but what I have doesn't match what people claim (I have the factory keyless system) so I don't trust that route.

Finally, if it's important, you can install (have installed) and aftermarket system. You get to decide HOW important as it might be more than you're willing to spend.