Jon saw the gleam of the pistol in his left hand and the shine of his rapier in his right.
Jon saw that he was holding an umbrella in his right hand and a blanket in the left. 
mnli hypothesis: Jon saw that he was holding an umbrella in his right hand and a blanket in the left.  premise: Jon saw the gleam of the pistol in his left hand and the shine of his rapier in his right.