A couple of thoughts and links to previous posts I made on the subject:
There are some sprockets where the holes are oversize for the original bolts... which should have the long shoulder as shown in Will's post. I got Acme to make me up bolts with oversize shoulders which were fineviewtopic.php?f=4&t=8152&hilit=sprocket
The bolts were originally fitted with locking tabs which, if correctly sized, will prevent the bolts coming looseviewtopic.php?f=4&t=8063&hilit=sprocket
Acme have these locking washers (I sent him one to copy and he had them at the AGM)
I can see no reason why the bolts should not be loctited in place as well.
John P makes a good point re not using locking nuts where the bolts are still threaded into the hub. The nuts would be OK if the threads in the hub were removed/worn away