I don't know what 'Shape' is, and 'detail32' is just an auto generated grouping that is used for setting that model's/object's LOD (level of detail), so no, neither of these are necessary
The 'detail###' grouping is only for swapping/hiding the model at certain distances, normally used to optimize the model by swapping the main model out with lower and lower poly versions of the model the further a player gets from it, Blockland mostly uses it to have a first-person and third-person only model for animations or details you can only see in while in first-person