Hello Andrzej and welcome to this forum.
I seem to recall seeing the van on a trailer for sale a year ago or so.. Feels good, certainly if you've been searching for a long time.
You probably know how these vehicles can rot, it is intensive rectification work but very satisfying to put right.
Most of the exterior panelwork is 1.00mm although the structural stuff Ive come across approx 1.2, 1.5 and 2.00.
The front Scuttle panel and 4 layers behind (all the way to the interior dashboard) rot out, as do the entry steps, upper A pillars and complete B pillars, Seem to be a result of 2 unprotected layers of sheet metal against each other.
The rear side panels do the same and you'll probably find the blisters and holes are in line with the supporting ribs on the inside.
On the upside, the panel work is less complicated than most vehicles of the following decades.
What are your plans, a running restoration or more ?