another magneto cover

this one is little mystery to me..first of all i don't know who made it.
ovbiously for pan or knuckle up to '62 configuration. but my question is pan,knuckle cam shaft end is blank, no key way like shovel/evo . how do you mount hex drive shaft for mag?
My guess is using degree wheel to set front piston on ign timing. and drill holes on cam shaft end and dowel pin mag drive shaft to cam shaft end? or turn down shovel cam to fit in cam cover? since pan and shovel rockearm ratio, cam lobes layout are close, i guess that might work. but on knuckle? ratio, cam lobes layout is totally diffrerent.
I guess this cam cover used to be available with special cam shaft for installation.
or someone just hand made it..
anyway,,i'll try to use it someday..