there is a security chip, the cabinet ID module is locked to only be used with SSB and the computer hardware (the make and model of which is coded to the game) is different. by the time you purchase a replacement CID, the security chip, and the upgraded hardware needed for GT (which is not available new anymore so you'd have to buy used), you might as well buy a brand new kit.
actually to correct myself, new hardware IS available, but you have to buy the newest 2015 version to be able to use new hardware.
the CID is a small square circuit board (1" 1/2 x 2") with a USB cable attached, put someplace inside the cabinet...it's ID number starts with something like 15-xxxxx or 17-xxxxx etc. the first 2 digits denote if its silver strike bowling, bags, or golden tee and so on. each has it's own number. I've looked into possibly reprogramming the CID's but it's way over my head.