Roger didn't want to deceive Whitebeard, but the page doesn't suggest that he wanted to direct Whitebeard to where One Piece was either. One Piece being in Raftel wasn't implied in their discussion, and it didn't have to be. Roger was the only person to have ever reached Raftel, so just reaching the island is a recognizable feat in itself and would probably be the very pinnacle of a Pirate's accomplishments. Perhaps that feat is what warrants the title of 'Pirate King'; a pirate overcoming all the challenges that they were faced with in their exploits and being able to reach the final island in the Grand Line which is implied to be a difficult task, would by all intents and purposes put them at the top of the top and would literally make them the 'king' of pirates. Whitebeard had accomplished everything else there was to accomplish, but his roster of achievements was missing that one thing and consequently, it could not be said that he managed to 'conquer' the Grand Line. By offering to direct Whitebeard to Raftel, the opportunity to do just that is what Roger was offering, but like we have often seen from Whitebeard, he had no interest in such things.
I believe that Raftel would indeed hold some kind of information about the ancient kingdom, but I'm positive that whatever they uncover in Raftel would not be One Piece itself. I'm a fan of the
theory from geez that talks about how One Piece, which I believe is the Ancient Kingdom, could be located under Reverse Mountain. I can't help but think about the 'Lost City of Atlantis' and the geez's idea would resonate well with that. One Piece not being in Raftel would serve as a way to create a new extended adventure for the Strawhats, an adventure that only they would be exploring after they had won the 'race' to Raftel. I think it is more likely that Raftel would simply hold the final Poneglyph. We know from the Skypiea arc that Poneglyphs are sort of like pieces of a puzzle that when linked together, would uncover the records of the lost history. It would make sense that the final Poneglyph, which is the final piece of the puzzle, would be in the final island of the Grand Line, Raftel. It is from the Poneglyphs that the truth of the lost history will be discovered, not from One Piece. Like my theory says, I'm betting on One Piece being the Ancient Kingdom itself which Raftel would give information to.