I have a 98 Gen 2 and had the same problem - one key. The locksmith said its a coded key (to rip me off) but I had one cut just in case i lock my keys in the Pajero and it works fine. Even if the key is in the house, so I don't think it has a coded key cause mine hasn't got one.
Thanks for the input.
Does it also start the vehicle?
If that is the case, i will be doing that today cause i feel a little nervous having just the one key.