Why Nokia didn't pick the S4 Pro for the 920 is a bit baffling. And no, the Chinese 920T does not count. There are probably more KIN owners than Lumia 920T owners on this planet.
I don't think it was out at the time, or the version that was out didn't even have an integrated radio.
Has it actually been confirmed that the Lumia 920T uses the S4 Pro? You would think they would have used it in the Lumia 925/928 if it was supported.
According to this its the same SoC as the Lumia 920, not sure who started spreading that rumor last year: http://www.developer.nokia.com/Devices/Device_specifications/Lumia_920T/