In regards to the rear cross member, I cant see where, if at all, it has been grafted on. please refer to the atatched photos of the rear.
also see the attatched photo of the spliced on front dumb iron, it is the only chassis extension/addition I can see that may have been grafted on.
If you compare the black S3 chassis section from the front garden (doesn't everyone have one?) this is the only real difference.
For the canvas, yes it is a 110 canvas, I was given it when i bought a complete station wagon for the back door, all for $200 delivered!
The only modification I did to it was slipped a length of 20mm plastic conduit over the leading strip and cable tied it to the prongs on the windscreen top, if anything it is too short in length over the tail section in comparison to the sides at the back.
Of note there has been some corner damage in the past, can see a tell tale line of rivits and a plate fitted in on the top of the passenger side back panel.