does "schulse-Eisenstein Galleries San Francisco"mean "a gallery named schulse-Eisenstei?"
schulse-Eisenstein Galleries San Francisco, California, u.s.a.
November 12, 1932
Herrn Martin Schulse Schloss Rantzenburg Munich, Germany
My Dear Martin:
Back in Germany! How I envy you! Although I have not seen it since my school days, the spell of Unter den Linden is still strong upon me—the breadth of intellec¬tual freedom, the discussions, the music, the light- hearted comradeship. And now the old Junker spirit, the Prussian arrogance and militarism are gone. You go to a democratic Germany, a land with a deep cul¬ture and the beginnings of a fine political freedom. It will be a good life. Your new address is impressive and I rejoice that the crossing was so pleasant for Elsa and the young sprouts.if it is, why does "Galleries " are in plural form?

Question

does "schulse-Eisenstein Galleries San Francisco"mean "a gallery named schulse-Eisenstei?"
schulse-Eisenstein Galleries San Francisco, California, u.s.a.
November 12, 1932
Herrn Martin Schulse Schloss Rantzenburg Munich, Germany
My Dear Martin:
Back in Germany! How I envy you! Although I have not seen it since my school days, the spell of Unter den Linden is still strong upon me—the breadth of intellec¬tual freedom, the discussions, the music, the light- hearted comradeship. And now the old Junker spirit, the Prussian arrogance and militarism are gone. You go to a democratic Germany, a land with a deep cul¬ture and the beginnings of a fine political freedom. It will be a good life. Your new address is impressive and I rejoice that the crossing was so pleasant for Elsa and the young sprouts.if it is, why does "Galleries " are in plural form?

Answer

Yes, it is the name of the galleries.  Although I think the "s" in "schulse" should be capitalized since it is obviously Martin's last name (along with U.S.A., of course).  It would probably have been clearer had it had an additional comma:
Schulse-Eisenstein Galleries, San Francisco, California, U.S.A.

As for "galleries" being plural, many art galleries do this since they may be displaying several different artists' works.  Using the plural indicates that there is more than one artist.  However, sometimes it is just an old marketing trick: if one is good, more must be better.