Congrats, you are connected to a tower that has been NOT reported as been upgraded, but the NID of 203 & 5 digit BID indicates you are connected to a NV upgraded tower.
Since you are a sponsor, you can see this tower has NOT been accepted as of yet, but most likely will be on tomorrow or this weekends update: http://s4gru.com/index.php?/topic/517-nv-sites-complete/
It's possible, and more than likely, 800 is either active or in test mode. What PRL are you currently on? It does make a difference, but your S4 is more than capable of picking up 800.
There's a great app called PRL helper that will allow you to flash a custom PRL that can help you "hunt" 800: https://play.google.com/store/apps/details?id=com.viper.prlhelperfree Again, since you're a sponsor, you can find custom PRLs here: http://s4gru.com/index.php?/topic/3059-800smr-s4gru-sponsors-prls/