With over 700,000 3rd gen 4runners sold in the US, there are bound to be exceptions, but generally speaking, if the key has a plastic handle (isn't all metal), it's got a chip. Of course someone could have just bought a plastic-handle key because that was what was available.

If you have a Security light that blinks and goes off when you start the vehicle, it has the immobilizer (chipped key).

If you don't mind just spending whatever it costs to have a basic metal key cut, it'll be easy enough to test. If the car starts, you don't need one. If it doesn't start, you need a chipped key. I bought 2 replacement OEM chipped keys on ebay for $30 (about half what the dealer wanted), you can get some chineesium stuff for a little cheaper but having both in hand, the OEM is Easily worth the extra few dollars from the quality/feel standpoint though (IMHO). You can absolutely program the keys yourself *IF* your chipped key is a "Master" (the security light goes off IMMEDIATELY when you put the key in the ignition). No Master key and the best you can do is the ~$100/key "clone" through a locksmith as not even a dealer will be able to make you new keys.