Looks like someone got themselves a rubber injection-molding machine..
My hunch is that most of these parts are re-molds of factory / NOS grips, so there’s going to be some loss of detail and dimension. Then again, maybe they managed to locate some old factory tooling for one or two types.. it’s definitely not unheard of.
I’d be curious to see the water pump rotors – they require some fair precision, and IIRC the factory parts have accurately ground surfaces on each sealing face.