So, I called the Austrian surplus shop and I spoke with the boss.
That boot is double stiched:
http://army-warehouse.com/10-servicecard-artikel/197-bh-feldschuhe-i-leicht-feldstiefel-neu.html
That boot is heavy high quality stuff, made in Austria by several traditional shoemakers.
You can get here a NEW double stiched high quality mountain boot for 160,-€
That is an incredible good offer!
He told me, that very similar older models of this boot he sells from time to time, when he gets them from the Austrian Army used. HE SELLS BOOTS THAT HAD BEEN MADE IN THE YEARS AROUND 1960, and they most times are still in usable conditions.
I don't know where else I could buy this quality for this incredible low price!
He told me, that he simply buys and sells a lot of them, nothing wrong with them.
I guess, I will buy them next autumn.
This different boot below isn't double stiched. It is made in a bit lower quality way to make it, because that is lighter and more flexible. It is single stiched. That's flexible but not absolutely bomb proof.
But it's lighter, more flexible and so the more comfortable option for long marches in flat country.
http://army-warehouse.com/10-servicecard-artikel/118-bh-feldschuhe-i-leicht-feldstiefel-neu.html
I guess, that's a very good offer too.
140,-€ for NEW boots, light model.
Austrian Soldiers get the light one and the heavy one. Originally they are meant for mountains the heavy one, for flat country the light one.
But he told me, that in the end it is a question of personal choice, what Austrian soldiers use in flat country.
One prefers the lighter one, one marches next to him in the heavier one.
In difficult mountain areas the heavy ones are recommended. They can be used with spikes too.
(I am not sure, if the heavy model still can be used with ski with the old binding, because I forgot to ask it.
In the 60ies similar boots were used with ski too, cross country and alpine down hill. But yes, used by Austrians who usually learn skiing before they learn speaking or walking! Nothing for beginners in my opinion.)