I just remembered something, the scene with Hiro and the dinosaur, he obviously did not have the sword (just the sheathe), but in the painting, wasn't the sword drawn? Was that an artistic inconsistency or is there a different future event involving Hiro and a Dinosaur?
I think it was just Issac's interpretations of what he saw. He may have seen Hiro with the sword in hand and assumed he was holding the entire sword, not a fake in the sheath.
I just checked it and the painting definitely is not him holding the sheath, but I am pretty sure we have seen that the paintings are potential outcomes and may not be 100%. Based on the fact that they go out of their way to show Hiro holding up the sword next to the dinosaur, that painting is definitely of that scene, i.e. not a future time where Hiro actually goes back in time to the Jurassic age.Maybe it is possible that the original sword was there and that it was replaced more recently by Linderman? He is way to interconnected with all of the characters to not have any idea what is going on. We have no idea who he is, but there is no doubt now that he is a central figure and may have more to do with the bomb than Sylar does.Actually, I will just throw this out now, but I have a feeling Linderman is the guy or one of the guys controlling HRG.