I would let someone know you appreciate the correct signage (mentioning concealed carry and not just "No weapons"). I'd love for you to post a picture of the sign if you have one.
The "correct sign" in accordance with the NRS 202.3673 Permittee authorized to carry concealed firearm while on premises of public building; exceptions; penalty.
Subsection 3. (a)
"A public building that has a metal detector at each public entrance or a sign posted at each public entrance indicating that
no firearms are allowed in the building,"
The wording of the NRS dictates the wording of the sign, even though the NRS is intended for concealed carry.
Change the wording of the NRS or just be prepared to explain it to those that don't/won't understand the NRS.
Some places, like DMVs, have changed the wording, on their own, to reduce confusion and confrontation.
While others like that it says "No Firearms" so they can tell you "that's the law", even though they are wrong. They are counting that you won't contest it and just be a good sheeple.