I don't have any blendshapes by default but yeah! I've used a few in a game I'm working on right now and they work great, especially with so few polygons it's easy to work with.
I've done these in unreal though, not godot, but I'm assuming they work the same way.
Viewing post in PSX Rigged Character Bases comments
If they don't use blend shapes, do you think there's a way then to make those body changes in-engine? Like, if the models are exported with multiple meshes, I can see being able to scale them or something, but basically I'm wondering if the body variations can be utilized without manually touching the model in Blender.