If your employer asked you if you had a firearm, and you knew it would get you fired if you answered yes, wouldn't you just lie?
Maybe Im splitting hairs here.... But IF an employer asked if you had a firearm in your personal vehicle, and IF you decided to NOT answer this question, utilizing your 5th amendment right..... Wouldnt that pretty much give him a good assumption that you do in fact own/possess one??
On the flip side of this coin, if you lied on the application or in the interview, most of these have a clause that if you lie, and they find out, you can be terminated at any point.
So, in conclusion, I do feel it would be for the best if the employer cant ask. Just my 2 cents, take it or leave it.
-MColford