Was there a misperception that the "bolts" were literally keeping his head from falling off? I missed that one.
Anyone ever read The Frankenstein Papers
by Fred Saberhagen? It retells the story from some other perspectives (including that of a highly intelligent monster). All the events are cast in a very different light. This story is set during the latter part of the Revolutionary War, presumably so it can feature a number of historical figures. But it somehow places the publication of Shelley's novel during the same time. I'm still trying to figure that out.