There's a large number of "production" pipes that are assigned numbers. These numbers represent a set shape of pipe. The Savinelli 320 has a nice following, so take that for example. The proper name for the shape is an "Author", but anybody can make an Author pipe, and they all might be a little different. Savinelli calls theirs the "320". Now, there are likely over 100 different Sav 320s throughout different families and styles, but they all will maintain the same shape. Search in Google or eBay for "Savinelli 320" and you'll see what I mean. Other production houses use numbering as well; Peterson, Brigham, etc... and they will all maintain consistency of their numbered shapes throughout their lines.
One problem with this is that it's harder to make a pipe that works with the grain of the briar when the shape and size is constrained. A pipe artisan making one at a time, all by hand can make minor adjustments as necessary to get the optimal product, and you might never see the same pipe twice, but a pipe coming off a production line with an obvious flaw or poor grain structure either gets thrown out or rusticated to hide those flaws. (you'll notice rusticated pipes are consistently lower priced, as they're more forgiving) The pipe you got is probably more akin to a freehand artisan pipe, but may not have met the standard of their "Autograph" series, so you ended up with a bad-ass pipe that no one else will likely ever have an exact duplicate of at a much more palatable cost than some of their $600 pieces.