Are you sure the name is Hainischs? Or is it just the genitive case of the much more common name Hainisch?
Exactly my thoughts.
There are German family names like
Hanitzsch
or
Hainisch
but
Hainischs felt very weird in the German language center if my brain.
The caption said Hainischs Steyer, so I am not so sure. But right now all I have is this caption
Hainisch it is then.
Hainischs Steyr is simply the genitive form like in English Mr Hainisch’s Steyr.
Great.
If you join the FB group (I sent you an invite) you can see the link
I will have a look there, too, thank you Pal.