Shearer alludes to this but I want to explicitly get it out on the Internet because I did original research and dammit I'm going to get a weblog entry out of it. Like most of Duchamp's alleged readymades, the original of "Fountain" (the urinal) is conveniently lost. The ones you see in museums nowadays are replicas made in 1964 or in the 1950s (?). But they're not replicas.
Here's the best picture I could find of the 1917 version. Note that there's one hole at the 'top' and six holes in a triangle shape at the 'bottom'.
Here's the one at the Philadelphia Museum of Art. It's got five holes in the middle in a cross shape. Here's the version at the Tate. It's got the triangle at the bottom, and a line of four holes at the top. That's identical to the one at SFMOMA, and it's the one in Duchamp's 1964 blueprint.
Here's the scale model from Boîte-en-valise. It's got some kind of raised area in the middle that has 11 holes in it, in a kind of arrow pattern. Finally, here's a shot of one that seems to have a line of three holes at the top, though it's barely possible the angle of the photo is obscuring a fourth hole.
This isn't rocket art history. All these replicas were made with a certain amount of care. They're all the same shape and the signature looks the same on all of them. But the pattern of the holes, the single most obvious thing about "Fountain" once you get past the fact that some bozo is exhibiting a urinal and calling it art, shows up in four or five permutations between the thing that Duchamp supposedly bought off the shelf at 118 Fifth Avenue and the various exact replicas and scale models made of it over the years.
Still unexplained is why Duchamp would do this. Some artists and critics are skeptical of Shearer's work because they don't see a motive. For instance, Arturo Schwarz, who made the 1964 replicas under Duchamp's guidance.
"Indeed if Shearer's theories were found to be true, then all the aesthetic that lies behind the creation of the readymade will collapse... But the truth is that most of Shearer's conclusions are wrong; why would Duchamp have had to deceive the entire world?"
One of the pieces [replicated in 1964] was Hatrack, a coat hanger that was originally lost by Duchamp. But the object produced by Schwarz has six hooks of equal length, whereas in Duchamp's photos and drawings the original had five hooks of different lengths. "The truth is that I too did a model with unequal hooks but Duchamp told me that the photos were wrong, I had to change it at my own expense," explains Schwarz.
"The photos are wrong"! Well, in point of fact the photos are wrong; the question is what to make of that fact.
There's a lot of space for theorizing, and I'm still exploring that space, but if I were Duchamp around 1950 I'd be a little disappointed by the rapid acceptance of the readymade concept. I'd want to set something up that would have on a sophisticated audience of artists the same effect as "Fountain" or "Nude Descending" had on the general public. Maybe that means doctoring old photos, maybe it means making fake replicas. All in a day's work for the guy who doctors photos all the time and whose mission is to destroy the concept of art.