Bought my 2001 SVT and it only had one key. Have been told I need 2 keys, both masters, to make 'slave' keys on my own in the Ignition switch, using the truck's computer.
Since I don't know if the lone key I have is a Master or Slave. Does anyone know if an Auto Locksmith can reprogram the computer for a new Master Chip Code if all I have is a Slave?

 

In short yes. A competent automotive locksmith can do this with a computer.

 

Yes, any competent locksmith, mechanic or Ford dealer can do this.

You can DIY with Windows Forscan (w/free extended license) and an OBDII adapter. You'll need another blank PATS key (not a clone) already cut for the cylinder. Get two of them, just in case.

Never heard of "Master" and "Slave" keys on any Ford, especially one over 20 years old. They're simply PATS keys (hardware store clones excepted)