It is not as though these model names are something new, as they have already made their fair share of appearances in the past. Earlier in March this year, there was an LG D850 was spotted over in a UA profile, where it supposedly comes with a 1440 x 2560 pixel display which would more or less a QHD resolution. The LG D851 also looks as though it is shaping up to be some sort of LG G3 variant that has support for a different set of radio bands, which might even set it to be a carrier-specific model.
The FCC’s papers also revealed that the LG D850 will run on LTE bands 2, 4, 5, 7, and 17, while the D851 supports LTE bands 2, 4, 7, and 17. It is nice to hear that both models do come with removable batteries, however.