I agree, but don't know much about those hub types. I most likely would have thought that the rear hub was original if the seller had not said it was updated in his listing info and followed up and said the same again after I reached out. I reached back out to the seller just now and he said he got it around 10 years ago (I thought he flipped it quick) and the person he bought it from had it in the family for a long time. I can only assume that was information somewhat passed on to him from the previous long time owner or else he would not have brought it up and made such a point about it. The patina is from an outdoors life right off the coast of SoCal.
The listing said this, "The bike is original except that the original coaster-brake rear wheel was at some point swapped for a Schwinn single-speed freewheel, with a nice very high-flange hub. The change also required the change of the chainring to 1/2" pitch, from the original 1" pitch. Given these upgrade parts are also quite vintage, I suspect the change was made in the 1950s."