Add in the fact that Kennedy refused having a more 'secure' vehicle, because he wanted the public to see him, and the fact that the Dealey Plaza route was a perfect spot to ensure a slow moving target, and you could possibly be correct.
Looking back at your comment, I see I was just being redundant.
Think I’ll go have a drink.
Actually, they were really wasn’t a “more secure” vehicle...SSX100—or “Queen Mary” wasn’t bullet proof...none of the tops were bulletproof, and Kennedy had been riding around in an open limousine throughout his entire administration...see the pics The Kennedy Detail...