One of the mysteries of the universe to me is “Why do so many 20th century pieces of furniture have wheels or casters on them?” A clue of sorts can be found in the generic name of many early 20th century items, those that are known as “Colonial Revival.” These pieces are modern replays of generally 18th century North American furniture originals, which in their own right often owe their existence to earlier European styles, but that’s another story.In the 18th century, carpet and other floor coverings were in much less general use than in the 20th century and as such, floor care did not consist of carpet sweeping so much as the mopping of wooden or stone floors.
A mass-produced sofa, even a pricey vintage piece, most likely bears a serial number somewhere on its body.
When I say "horsehair', the tail and mane of a horse as well as the "tuft' at the end of a cow's tail are sources that I think of.
There probably are other animals that have the same type of slick, stiffish hair, but horses' tails are the only ones to have fibers long enough to weave with without spinning. Being hair, it is a protein fibre, so it has more or less the same properties as other protein fibres.
On newer pieces, the tag may be on or underneath removable cushions or the skirt of a couch.
Determining the manufacturer also determines the potential date range of the piece.