8 thread and 10 thread ??? locks for 99 Pathfinder

I lost my only key to the truck and just took drivers door apart to take the lock out and take it to locksmith. Both locks (drivers door and ignition) were changed in a past by a previous owner.
I just have talked to a guy at a local dealership and he said that if I try to take the lock out the door and make a key for the truck, it's not gonna work. He said that ignition lock is a 10 thread and door lock is an 8 thread one. So, it's not gonna work because last two threads will not be available. Is that right? Doesn't sound right at all...