According to the slide, the phone will have under its hood the recently announced Samsung Exynos 4212 which will run at 1.8GHz with 2GB of RAM. The back camera will be a 12MP shooter with a backlit CMOS sensor that improves picture quality in low-lighting situations. The display is said to be 4.6inches of Super AMOLED Plus HD, which is the same display expected to be used on the Google Nexus Prime, but with true RGB matrix, not the PenTile arrangement.
Other details not mentioned on the slide include NFC and LTE support and will not have the curved glass on the display like on the Google Nexus S. Additionally, while the Ice Cream Sandwich build does not require the four buttons on the front of the device, the Samsung Galaxy S III will have them anyway. Lastly, the phone will look a lot different than the current model so that Apple won't be given a chance to block sales of the device by telling a court that it looks too much like the Apple iPhone. Apple and Samsung are expected to hear a ruling this week from a District Court in California on Apple's request for an injunction preventing the Korean based company from selling certain models in the U.S., including the Samsung Galaxy S II, because they look too much like Apple devices.
As far as the legitimacy of the slide is concerned, the white space around the pictures of the phones on the slide indicate that someone might have used "paste and copy" and the art work on the slide seems a bit unprofessional, so keep in mind that these specs could simply be coming from someone's creative-but devious-slide.