1 --- If the pipe to be conterfeited was made in a production line, the machinery and tools used left "fingerprint"-type indications/evidence that is more difficult to replicate manually than the pipe is worth, money-wise.
Here is an example. Consider a common wooden clothespin. It's worth 25 cents. It consists only of two pieces of shaped wood and a length of coiled wire.
Give the most skilled hand-tool worker who ever lived a block of the proper wood, a length of the proper wire, and a handful of legit sample clothespins to use as a pattern, and tell him to fabricate a exact copy. One that cannot be spotted AS a copy.
Doing it completely by hand would be impossible, of course. The only way would be to find or make tools with exact cutting radii, make jigs to space the cuts and angles exactly right, build forms for coiling and shaping wire, discover the the correct annealing and heat treating temps to created a spring of the proper tension from that wire, and on and on. Thousandths of an inch would matter, and the proper tell-tale tooling marks---or the lack of them---in the finished piece would also be critical.
In other words, he'd have to, essentially, make a small scale clothespin FACTORY first.
And the payoff once that was done? Zero. A perfect copy would be worth no more than a legitimate one. 25 cents.
2 --- If the pipe to be counterfeited was made by a single person, the style and form becomes a "fingerprint" of its own. Give the forger a block of the proper wood and a length of hard rubber rod and repeat the exercise. Make a pipe that captures the ARTISTIC ESSENCE of famous carver X, so that collectors of his work can't tell the difference.
Well, that describes what many thousands of aspiring pipe makers have been trying to do for decades. And the very few who ever became good enough that their pipes sold for four figures didn't need to copy someone. Didn't WANT to copy someone. Why be anonymous and risk being exposed as a forger when legitimate fame and fortune (the PipeWorld version, anyway) is the other---and simpler---option?
The net result:
There have been, and will always be, Nigerian Scam-type low effort "fakes" that prey upon low information buyers. Cheap existing pipes that are marked with a famous-maker name. The equivalent of those Lincoln Town Car stretch limousines with a Bentley hood emblem that rappers are famous for.
Higher effort "require a close examination to identify" fakes simply don't exist for the reasons given.
The only exceptions known is a matter of semantics. Fake by strict definition because they were unauthorized, but legitimate in every other way. Authentic materials, techniques, tools, workers, and so forth. They were simply made after hours, smuggled out of the shop, and sold privately.