4 Large Realistic Teddy Bears

I picked up these 4 bears is San Marcos, Ca. They seem to be made by all the same person. Realistic looking. Brown glass eyes, plastic nose with some sort of coating, mouth seems like painted on rubber or plastic material, backs have large realistic bump with divit to look like bear shoulder blades, claws are very realistic with some sort of plaster or clay(on a nail that is broke you can see they have metal wire inside to be sturdy), vinyl black paw pads, white batting filler stuffing, red bow around each neck. I was told these could be considered artist bears, or advertising bears. I would love to know more about them, I cant find any info on bears of this size. I am guessing 1960's because of the materials used, but that is just an uneducated guess and I hope someone can actually point me in the right direction of these bears origin.

Largest is 60", black bear, standing, he has a skeleton made of metal pipes, extremely heavy.

2nd standing bear is smallest at 36", brown bear, also has metal pipe skeleton, very heavy, rotating neck joint made of white plastic.

3rd bear is large sitting bear, brown bear, with wire frame for bending into positions, lightweight, but very big.

4 bear, is smaller sitting bear, also with wire frame for gentle bending, rotating neck joint made of black plastic.