Tail light housing bolts

[Bud5000]

What is the head shape of the bolts that hold the Plus 2 tail light housing to the bodywork? Parts book says a hex head but a slotted head might work better?
What have other owners used?

[alan.barker]

Hex head and they are "set screws" + big flat washer + spring washer.
Alan

[Bud5000]

I've gone with internal hex bolts, that way I can get the Allen key onto the head of it. I modified the reverse light bulb metal shroud to get the bolt in after the shroud is rivited in place.
I made plates to retain the light housing against the body as the curve of the rear made it difficult to use a large flat washer.
All seemed to work okay.