The stocks are mostly interchangeable between different 64s. The original Cooey 64s didn't have the inlet for a receiver safety (pictured stock does have inlet), as they didn't have that kind of safety. Also pretty sure the current synthetic 64 stocks have 2 screws for takedown, and not just one like the originals. All can be swapped with a bit of fitting.
I would guess Lakefield made the pictured stock.