You know, if we had access to the formal forensic fingerprint analysis that matched the palm print to Oswald, at the very least it would tell us if there was a rush to judgement.
If it showed a legit match then we can move on and debate how it got there, etc., but until such time, there is much wheel spinning to be had regarding the palm print.
As far as how the rifle ended up on the 6th floor goes...it was planted, of course, without any of Oswald's prints on it. That tells us that Oswald was a patsy that didn't handle the rifle, just like he claimed. Then everything fits and we can move on from the untenable lone nut narrative, which is the fringe opinion these days.