Apple has a specific methodology regarding the names of the icons, for applications, standard and those specially made for Retina Display, that is, the icons for standard (for iPhone 3G/3GS) have standard names, while the applications specially made for Retina Display have in their name the code @2x. These names appeared after the launch of the GM version of iOS 4, that is, after the official presentation of the terminal in June. It seems that even then Apple made references to the possibility of implementing Retina Display on the iPad. In the above document discovered by 9to5Mac in June last year we had an explanation for the naming of applications for Retina Display and notice that the explanation is made for both iPhone and iPad.
As you can see in the image above, Apple notes “MyIcon~ipad.png” for the standard iPad existing today, and a "higher-resolution variant"MyIcon@2X~ipad.” As you can most likely already tell, Apple here is likely referring to a higher-resolution iPad.
The image dates from June 14, 2010 and corroborated with the latest rumors regarding the iPad 2 tablet, the conclusion could be drawn that the new tablet could have a Retina Display. On the other hand, Apple could have provided those explanations for informational purposes only, without any connection with the implementation of this type of screen on the next model of the tablet.
