No, I think what he’s saying is that the alleged “crease in the box where a rifle might have lain” was a flight of fancy.
That's correct. The police saw the Smoker's Nook and imagined it to be a "Sniper's Nest". They supported that imaginary idea by imagining that the sniper had sat on a box to the rear of the stack of Rolling Readers and used the stacked Rolling readers as a steady rest for his rifle. And they imagined that the crease on the top box was created by the recoil of the rifle.
And that's what they told us trusting peasants....( LBJ called us pissants) .... We had no way of knowing that the tale was physically impossible.
A 5'9" man sitting on a 12 inch box would have his shoulder about 32 inches from the floor .... The Rolling readers were stacked about level with the shoulder of a 5'9" man sitting on a box. The angle to the car ( according to page 100 of the WR) was nearly 27 degrees.) 27 degrees from the top of the Rolling Readers is about 52 inches up from the floor at a point 3 feet to the rear of the boxes, but a 5'9 inch man's shoulder would be about 32 inches up from the floor.
A 5'9" man holding a rifle resting on the Rolling Readers could not decline the muzzle of the rifle down onto Elm street... THAT is a fact.