If you have push button ignition then yes there's a chance your car is vulnerable.

Any CAN bus? No, it takes time to sniff the bus and get all the control messages, older cars may be especially vulnerable since they likely don't have as many security precautions in place.

CAN has been in cars for quite a long time, the infiltration systems haven't due to high-cost/lack of electronics.

On a side note, the hack talked about in the article could be performed by a Arduino UNO and a $5 can bus transceiver.

Age doesn't really matter in this case. This is laziness on Toyotas part by not authenticating the messages between the "Smart Key" ECU and the main engine control microcontroller.