Actually it only has to be posted in order for it to be a prosecutable offense... It still is a no go zone and they can still ask you to leave and escort you off if it is discovered or believed that you are carrying...
As can any business give a verbal 30.06 notice.
But the statute says the prohibition "does not apply" unless given notice in accordance with 30.06 .... just like any business.
So by that train of thought, ALL businesses are "no go zones" because they MIGHT give you verbal notice maybe.
Subsections (b)(4), (b)(5), (b)(6), and (c) do not apply if the actor
was not given effective notice under Section 30.06
Therefore the prohibition "does not apply" to licensees, UNLESS they are given notice in accord with 30.06 .... same as any business.
One could be prosecuted for failing to comply at ANY business that places a valid compliant 30.06 sign or gives verbal notice under 30.06
AND it is not a violation if the sign is NOT in compliance with 30.06, such as a gunbuster sign.