Back in the 1960's herters actually had several different molds.
In the 63 line they had a mallard, Pintail, diver and Coot body all of which were ran on steamers basically by hand just as people make them now with the decoys unlimited molds.
in the 72 line I am only aware of 2 bodies over the years however some feather detail changes were made but there may have been a 72 pintail body as well but I have yet to see one.
And yes many different colors of foam were used back then when they were made during the steam boiler days of hand producing them these bodies are all after the keel was added to them in the molds.
They also had rabbits, squirrels, crows, doves and even owls they made as well back in the day.
It would be neat to see a photo of all the different versions of the herters bodies and changes over the years. maybe someone someday will create a history site for Herters Decoys.