They come up on auction sites from time to time. There's also a trade in generally non-firing replicas in Kabul and Peshawar.
According to a June 25, 2014 article in 'Stars and Stripes', Afghan smiths are still turning out allegedly functional jezails, however as these "often employ barrels scavenged from 19th century made muskets", their operability is probably a function of one's own concepts of personal safety.
From Kipling's "Arithmetic on the Frontier":
A scrimmage in a Border Station,
A canter down some dark defile,
Two thousand Pounds of education,
Drops to a ten-Rupee jezail.