What a brain dead statement!! “if you believe you have been aggrieved by these signs." That is his conclusion after reading the NRS and informed the policies are in violation of Nevada State laws!? Makes a person want to open up a large can of hissy fit on him.
Look at it from a different angle -- he tells you that he believes that he has no authority to open the lock, then GIVES YOU THE KEY so that you can give it a try!
Remember, to file an action against the government you must have "standing," a valid and apparent cause to be involved, or the action is automatically dismissed with prejudice (meaning you can't try again). If your complaint states that you are personally "aggrieved by these signs," then you HAVE standing.
A courthouse is not the same as a park, and will take a harder push to get things moving, but the legal beagle has told you how to do it.
Also, to file suit against the government, first you must give fair warning, to permit them to mitigate prior to the costs of a trial. That letter goes to the same guy who just told you what to put in the letter! If he is on our side, or even just neutral, with that letter he DOES have authority to address the issue. Even if he is opposed, with that letter he MUST address it. As it won't take much research (he has probably already done it) to see that the sign is a violation of the law, the threat of lawsuit is likely to get results, without having to do more than send the warning letter . . .but until the key is used, he has no way to move on it.
You guys down in the Sharp End owe a debt of gratitude to the guy up here who kicked Sparks off of center, because that precedent will work all over the state -- even in Northeast LA.
I'm curious, though, why that new group down there hasn't checked in on this. It seems like a good way to get a little live-fire training.