Both cameras will accept international dark-slides (film holders) and certain roll-film backs - those designed for spring-backs. But that's as far as inter-changeability goes. The Graflock back will of course accept all types of international roll film holder.
The simple answer is no I have both cameras and they are quite different no parts are interchangeable, the focussing rails and front standards differ, as do the lens-boards. I bought two Graphics last 18 months ago off ebay sold to make one good one from the two the seller neglecting to say one was pre-Anniversary and the other A Pacemaker Speed Graphic, so I know from experience how different the parts are.
Don't worry about the focal plane shutter, if it works great it's an option you can use, otherwise just leave it open and use the camera as if it doesn't exist.
Ian