Nissan Repair: ignition switch 1982 720 gas truck, screw driver, wrecking yard

Question
My key broke off in the ignition switch and I am going to replace the switch. In trying to remove the switch I have found that there are 4 bolts holding it to the steering column. 2 of these have Phillip heads.  The other two some sort of plain round head that I have never seen.(no slots for a screw driver of any kind or no angles for any wrench). Is there a special tool to use to remove these. How do you remove the switch from the steering column.
Thank You , Bob

Answer
Bob,

The other two bolts are not bolts.  They are rivets and you have to cut them out and replace them with bolts.  Otherwise, you might get a column from a wrecking yard and just replace it.  Getting the two rivets are that difficult to remove I would recommend a wrecking yard unit.  You see, the column collar is soft metal and the bolts are hard, so you will end up cutting into the collar if you are not careful.