No Bill - heated and pressed in a heated cast iron die-set that was cramped tightly together. Both horn and turtle are natural thermo-plastics. A long, long time ago, Brownell's even offered rifle fittings made from pressed horn:
The art has been around for a very long time. there are several known 17th century / early 18th century practitioners: John Osborn, Samuel Lamberlet and John Obrisset.
Plus a couple of my old ones:
Regards,
Neil