boring_e621_fluffyrock.pt was trained on the model fluffyrock-576-704-832-lion-low-lr-e15.
boring_e621_fluffyrock_v3.pt was trained on a later epoch of the same model (possibly e23?).
boring_e621_fluffyrock_v4.pt was trained on fluffyrock-576-704-832-960-1088-lion-low-lr-e27.
It does not work well with any version of the model having "vpred" in the name, but other versions seem fine.
Note that unlike boring_e621, these fluffyrock versions do not need to be preceded by the word "by". They were trained without it.