Did your grandparents say that he actually stayed there?
If so, do they have the hotel sign-in book (Registry) with his signature to prove that he was there and help to support the validation that this could belong to Kit Carson? (Validate time line and signature)
If he did stay there, where was he going to? How was he traveling?
Why would a trunk belonging to Kit Carson be left in the hotel? (Reason)
These are many of the questions that would have to be answered to help validate (if at all possible).