Rob,
The front flaps that came on my truck were made of rubber and obviously post war fabs. I cannot say what, if anything was inside the canvas 'pocket' of flap material.
The rear flaps were is great shape ( from the West ) and were just canvas pockets with nothing in them. No horse hair, or any other padding. To weight them down a 1/8" x 1.5 x 12inch strip of steel flat stock was slipped into the bottom, then sewn shut.
I have left a sample with a tent maker in Tillsonburg, Ontario and hope to have the rear set back this week. I will post a before/after snap when they arrive in B'Ville.
As my front clip is still on 2 saw horses in the garage I did not want to stab at fabbing the front flaps, but I shall get my template material out and see how close a HUP flap is to a 15cwt.
Thanks for the resto pix.
Stewart
5 1/2 weeks to BB2