There are multiple reports that some of the new 21.5-inch iMacs are shipping with an "Assembled in USA" label.
Fortune is reporting that one of their readers walked into a San Jose, California Apple Store and purchased an off-the-shelf iMac that was assembled in the United States. During their teardown, iFixIt also found that their iMac was assembled in the USA, as shown in the photo below.
Fortune acknowledges that this has been noticed online as far back as 2006, though mostly for build-to-order Macs
As it turns out, this is not the first time the assembled-in-USA question has come up. There are several threads on the topic in the Apple support site dating back to 2006. The consensus seems to be that only units made to order -- say, with an extra-high-capacity hard drive -- get their final assembly in the States.
There's a suggestion that the non build-to-order U.S. assemblies are a new phenomenon, but the distinction is far from clear.
Back in 2010, members in the MacRumors forums had reported that they were also receiving new iMacs being labeled as "Assembled in USA", though their exact configurations weren't discussed.