Mounting spark plug wire guards on 39 A JD

[Farmallb]

I got the wpark plug wire guards from a salvage yard, so I dont know if or what year tractor they went on. Theres a tab with a small hole in it onto the guard where the wires come out. The paint around that is old green. There is a rusted spot beside it that fits ther width of the hangers.
When I took the hangers off, There was still one arm of the pipe attached, and the tab was still on the bolt, tho broke off from the tube.

Question I have is, Does the tube mount centrally with the tab with the hole going through it also going through the hangers, OR do the hangers mount to one side of the tab>
 

[RLA]

I thought the bracket from fan shaft housing
mounted to the left of where the wires go into
the tube.
 

[Farmallb]

I mounted it to the left, and it looks OK, BUT what is/was the tab for with the little hole in it, that was made when they cut open the slot for the wires to come through and bent the tab back upwards?
 

[greenmech]

Think it was for a rubber block for clamping the wires. Ron Mn.