E3 is fast approaching and gaming publications left and right are posting their tamest and wildest predictions for the biggest annual gaming show. It's generally accepted that Rockstar Games doesn't flaunt its titles at a big show like this but there have been exceptions.
Last year there were also rumors of Rockstar possibly showing off some Red Dead Redemption 2 footage at E3. However, most likely due to the delays, this never came to pass. This year may bring change for a number of reasons and the biggest one can be traced back to an E3 from a few years ago.
In 2014, Rockstar Games announced the Enhanced Edition of Grand Theft Auto 5, which was a port of the game coming to PlayStation 4, Xbox One and PC, during Sony's press conference, showing footage of the Enhanced Edition running on a PS4. Though it's true that this wasn't a dedicated Rockstar presser, and the company is a rare presenter at E3, there are other examples in the past - like the Agent announcement which was also tied to Sony.
Rockstar Games and Sony go way back, with the PlayStation 2 being the real first home of the 3D era GTA games. Agent was supposed to be a PlayStation 3 exclusive. With the two companies being so close, it wasn't too surprising when Red Dead Redemption 2's marketing material was PS4 co-branded.
Limited timed-exclusivity on Red Dead Redemption 2 DLC has already been confirmed, showing that there is some kind of marketing deal going on between Sony and Take-Two Interactive. This leads to the possibility that Red Dead Redemption 2 might get some time in the spotlight at E3 2018 - just not via a dedicated Rockstar panel.
Take-Two doesn't usually mix the affairs of 2K and Rockstar Games, with the former developing and publishing enough games frequently to warrant their own presser. This way instead of a unified publisher-based conference, Rockstar's footage might be passed on to a business partner - in this case, Sony.
Sony has been using the PS4's larger library of console exclusives to push the marketing of their machine, and even if we're talking about timed DLC exclusivity here, it still fits the theme. Showing off such a highly anticipated game like Red Dead Redemption 2 using a PS4 would make sense from a marketing perspective.
As for the specifics of what we can expect, there is really no telling.
One good guess would be that the gameplay demo shown at the press event will now be shown to the public as well, or at least an abridged version of it. Nobody should be expecting any hands-on demos, but some actual gameplay footage instead of the edited and scripted in-engine trailers would be nice.
Additional information regarding the game may also be released leading up to or right in the wake of E3, however if Red Dead Redemption 2 isn't shown off during the event, don't expect any tangential info to be revealed by Rockstar during that period. They like to publicize their games when there is no competition for attention, which is why they usually avoid E3.
E3 2018 begins on the 12th of June.