I know a bit about upholsering and can tell you that the pillow is full of feathers, not foam. Also, the stuffing is old, possibly horse hair. If it has been reupholstered they did an excellent job but it may very well be the original fabrics. Even the dust cover underneath appears original. My guess is that this was sitting somewhere like a parlor where it was rarely if ever used.
Note: Even if it's not what we think, that's okay. We like it for its look. However, I saw one in an antique book very much like it that was appraised at $3,000. Your comments will be greatly appreciated!