It will work but Will show Sprint as well...
As Photon 4G is Sprint branded, it picks Carrier name from Local file and from PRL/NAM
You can see in Network Selection Mode it shows
1. Sprint only
2. Any CDMA
3. GSM
4. Automatic
As of now CDMA-UIM are not properly working on Photon so we have to use it with flashed NAM/PRL. And that carrier name will be picked up from local resources only...i.e Sprint