B posts on 403

[mikebro]

Here are some photos. All pictures are of the RHS of the car - ie back of car to the left. The rear of the door opening is on the right with the door removed. the rear right wheel arch would be off the picture to the left. The photos ending 91 and 31 are as found, having removed the bodged galvanised plate that had been riveted over the aluminium. 33 is after I have cut away the corroded aluminium, exposed the bottom of the B post and cut away the corroded steel from it. On 31 and 33 you can see what's left of the bottom of the aluminium as it curves under the bottom of the steel on the B post. My question concerns how the aluminium is fixed underneath - crimped over or riveted through?