Apple has clarified it's web page about the 5s. There is a CDMA version 1533 and a GSM version 1533. The unlocked T-Mobile iphone 5s will not work on Verizon because it will not have CDMA.
From Apple:
The unlocked iPhone includes all the features of iPhone but without a wireless contract commitment. You can activate and use the unlocked iPhone on the supported GSM wireless network of your choice, such as AT&T or T-Mobile in the United States. The unlocked iPhone will not work with CDMA-based carriers, including Sprint and Verizon Wireless.
http://www.apple.com/iphone-5s/specs/
From Apple:
The unlocked iPhone includes all the features of iPhone but without a wireless contract commitment. You can activate and use the unlocked iPhone on the supported GSM wireless network of your choice, such as AT&T or T-Mobile in the United States. The unlocked iPhone will not work with CDMA-based carriers, including Sprint and Verizon Wireless.
http://www.apple.com/iphone-5s/specs/