Can't tell from the photo, is there a separate ground wire (not talking about the kill switch tab) coming out of the coil that has to be placed under one of the mounting screws? In older modules, the coils were wound on a bobbin and the bobbin was pressed onto the laminated core and bonded there but as coils are autotransformers, the primary and secondary windings have a common ground that must be grounded to the cylinder so a separate ground lead was brought out of the coil to do this. The bobbin with the coil could usually be removed and replaced with no damage. More modern modules appear to have the coil wound directly on the core and the ground lead is spot welded to the core and the whole thing, including the semiconductor package is potted in a very good epoxy. If your coil has only the high tension lead and a tab for the kill switch wire, you won't be able to separate the coil from the core without damaging the coil but if you do manage to get it off, you might be able to find an older type of coil that can be fitted onto the core. Would be a very frustrating exercise.
