This appears to be the proper "ban guns" sign. It is visible from a distance, 2" block letters, etc. One might argue the lateral viewing ability because of the building structure.
"(i) the requester has prominently posted a conspicuous sign
at every entrance to the establishment containing the following
language: "(INDICATE IDENTITY OF OPERATOR) BANS GUNS IN THESE
PREMISES."; or
(ii) the requester or the requester's agent personally
informs the person that guns are prohibited in the premises and
demands compliance.
(2) "Prominently" means readily visible and within four
feet laterally of the entrance with the bottom of the sign at a
height of four to six feet above the floor.
(3) "Conspicuous" means lettering in black arial typeface
at least 1-1/2 inches in height against a bright contrasting
background that is at least 187 square inches in area.
(4) "Private establishment" means a building, structure, or
portion thereof that is owned, leased, controlled, or operated
by a nongovernmental entity for a nongovernmental purpose."
FYI, I did ask the senior Dr there about the sign, he said that it was a clinic and they are there to heal, not injure people. I guess everybody thinks that Permit to Carry holders are the "bad guys" and just run amok shooting people.