So how would you set this up in case you have to revisit your model at some point to either fix a problem or perhaps add to the model.
Would you keep the original model with all the separate meshes, and then go through this vertex grouping and re-rigging each time you had to export?
If you want to keep your model with separate parts (in case you want to change one or more of those parts) then you should create a split by saving the file as something else before starting the re-rig. Doing that means you have the whole object to export and you have it separated into parts ready to swap/change parts.