Lets look at this in a reasonable manner. The officer was polite, and made a request of you-not a demand. I fully understand the reason for the request, most of the states that have the "must disclose" doctrine did so at the request of police agencies. The reason is really really simple. If the cop knows you have a legal weapon it takes a potential suprise out of the situation, and where firearms are involved, suprises are almost always bad-sometimes fatal.
Just suppose that you had a legit reason to emerge from your vehicle(cops HATE this), but they do happen, and while doing so he catches a short sight of your gun, everything, and I mean everything has now changed. He is confronted with an armed person. Even at my advanced age and loooong experience, here is what I am going to do:
1. Hit the "all call" button on my computer, asking for back up from every and anyone able to respond,
2. Ticket book and pen are replaced forthwith by either my holster weapon(BHP 9mm) or more likely by my "car gun" (Colt 1911 concealed near my seat that I can reach instantly while seated),
3. Polite conversation is replaced by "stop where you-NOW, get down on the ground-NOW, etc.
4. This monologue is transmitted over a ready to go bang pistol.
With my experience I might take a chance on your "looking OK" or how scared you look, someone with lesser experience(which is just about everyone these days) just might shoot you if you are not on the ground by the end of the last breath of "NOW".
There are too many A$$ holes out there today, and I do not mean CCW folks, everyone of them I have encountered over the last almost half century were nice folks, most of whom I wouldn't mind as neighbors-If I wanted people as neighbors.
Think about it, on/off duty cops shoot each other with alarming frequency. All of which would have been avoided if everyone concerned had known that the other guy was carrying.
If I get stopped off duty (less frequently these days) I immediately tell the officer (without removing hands from the wheel) I am Captain------- and my weapon is wherever it is.
Puts everyone at ease, cop knows what to look for and does not get excited when he sees it.
IN matters of firearms, ANYTHING we can do to reduce misunderstanding is worth it. I am not necessarily infavor of a law requiring disclosure, but I am in favor of no suprises-for everyone.