I think, for a 38':
Early Executioners had no steps, flatter deck, and no walk around on the gunnel. Side by side engines.
Lightning has large steps, a raised deck, and a walk around on the gunnel.
Early Lightnings are side by side, later are semi stagger engines.
Later Executioners have the Lightning stepped bottom with the flatter deck and no walk around. Side by side engines.
I'm assuming the Executioners have a wider, longer cockpit.
Latest Lightnings have a full stagger engine set up. No cockpit.