You seem to have conducted yourself fine and asked all the right questions in a way that doesnt make gun owners seem like psychos. I think you did just fine. The only thing I would be careful of is if an owner of any business outright asks you to leave.....do so without arguement so you dont get in trouble with the law.

Did the manager ask you to leave when you refused to take your pistol off and put it in your car or where ever?

I also would have mentioned you will in the future protest with your wallet for his personal beliefs on firearms and not being company policy and that you would take your business elsewhere. Was it his personal firearms beliefs? My understanding was it was from your post.

I hope you did some good if you ended up finishing your meal and that the douche will not make an example out of a future patron who is OC while they have some hot wings.