A peek into the code for Apple's upcoming iOS 5 reveals two new iPad 3 models potentially in the works, according to sources at tech site TUAW.

Checking out the code files for USB devices in the iOS 5 firmware, TUAW uncovered references to an iPad3,1 and an iPad3,2.

The current iPad is identified as three separate models internally--iPad2,1 (Wi-Fi version), iPad2,2 (GSM version), and iPad2,3 (CDMA version). So the two models found in iOS 5 may be for a Wi-Fi version and a cellular version, suggesting to MacRumors that the iPad 3 cellular version would be a "world-mode" device capable of running under either CDMA or GSM.

The code contains no mention of a new iPod Touch device, which Apple typically unveils in September. Sources noted by TUAW believe that could mean Apple is reserving that month to shine the spotlight on a new iPhone instead.

The new iOS 5 code also points to two new iPhone models--an iPhone4,1 and and iPhone4,2. However, those references had already been discovered earlier this year in the code for iOS 4.3, according to MacRumors.

It's important to note that such code references as these doesn't always lead to actual products. An iPhone 3,2 (which actually would have been a third iPhone 4 model) mentioned in earlier iOS code never materialized.