Yes, many Stahlwille and Hazet tools were used by Porsche.
I have several Stahlwille torque wrenches, some from the 50s and 60s.

http://forums.pelicanparts.com/uploa...1584474999.jpg

http://forums.pelicanparts.com/uploa...1584475051.jpg

Another old one...

http://forums.pelicanparts.com/uploa...1584475670.jpg

A few more oldies...

http://forums.pelicanparts.com/uploa...1584477375.jpg

http://forums.pelicanparts.com/uploa...1584477422.jpg

Jon your collection of vintage German shop equipment and special tools is the finest I have seen. It needs to be in its own museum someday, a diorama set up like a Porsche workshop in the 1960s.

John, in the late 70s I was disappointed that torque tools in mkg (meter-kilogram) and mkp (meter-kilopond) were no longer available new :-(
Those were the torque values used in the old Porsche manuals.
So while my new tools were calibrated in Newton-meter, I also bought tools with the older values if I found them in nice condition. I've got quite a few old ones, mainly Stahlwille and Rahsol.