Both the SAM4s SPS-520RT and SPS-530RT use the same keyboard. The replacement keyboard comes in the factory standard configuration.
If your keyboard is not in the standard configuration make sure to remove the optional key tops you have added. You may also want to retrieve the labels from your old key tops as well unless you plan on making new ones.
The keyboard is pretty easy to replace on your own, if you want it replaced by us please call us at 1-800-863-2274 to discuss the options. If you will be doing the work yourself please make sure you back up the register and unplug it from power before removing any parts.