Dunhill pipes are almost certainly in the same category. Lots of obvious cheap fakes, but some really, really good fakes too.
Pipes are handmade/hand-finished items that do not follow the fountain pen, wristwatch, iPhone, clothing, handbag, etc. "appliance" model of counterfeit merchandise.
The bottom line is anyone with the skill and tools to make undetectable Dunhill fakes would do a
LOT better money-wise making his own line of pipes. Besides carving chops, he'd also have to know how to make fake stamps and know how to use them in various correct combinations.
And, since a steady stream of fake "new old stock" output would attract attention (because anything made after 1970 or so is worth dramatically less than what was made before that time), he'd have to also perfect an artificial aging process.
And on and on. There are too many other pipe-specific and Dunhill "gotchas" to list.
"But people fake handmade fine art like paintings and sculpture all the time!" you say? That's an entirely different thing because of the money involved. There is fifteen billion dollars in play annually in that game:
http://imgpublic.artprice.com/pdf/rama2014_en.pdf
Going to extremes is worth it when the object is worth six, seven, or eight figures. The most expensive tobacco pipes ever sold, though, don't pay enough in buyer's premiums for Sotheby's or Christie's to even list them.